/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/arbitrary-1.3.2/src/unstructured.rs

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// Copyright © 2019 The Rust Fuzz Project Developers.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Wrappers around raw, unstructured bytes.

use crate::{Arbitrary, Error, Result};
use std::marker::PhantomData;
use std::ops::ControlFlow;
use std::{mem, ops};

/// A source of unstructured data.
///
/// An `Unstructured` helps `Arbitrary` implementations interpret raw data
/// (typically provided by a fuzzer) as a "DNA string" that describes how to
/// construct the `Arbitrary` type. The goal is that a small change to the "DNA
/// string" (the raw data wrapped by an `Unstructured`) results in a small
/// change to the generated `Arbitrary` instance. This helps a fuzzer
/// efficiently explore the `Arbitrary`'s input space.
///
/// `Unstructured` is deterministic: given the same raw data, the same series of
/// API calls will return the same results (modulo system resource constraints,
/// like running out of memory). However, `Unstructured` does not guarantee
/// anything beyond that: it makes not guarantee that it will yield bytes from
/// the underlying data in any particular order.
///
/// You shouldn't generally need to use an `Unstructured` unless you are writing
/// a custom `Arbitrary` implementation by hand, instead of deriving it. Mostly,
/// you should just be passing it through to nested `Arbitrary::arbitrary`
/// calls.
///
/// # Example
///
/// Imagine you were writing a color conversion crate. You might want to write
/// fuzz tests that take a random RGB color and assert various properties, run
/// functions and make sure nothing panics, etc.
///
/// Below is what translating the fuzzer's raw input into an `Unstructured` and
/// using that to generate an arbitrary RGB color might look like:
///
/// ```
/// # #[cfg(feature = "derive")] fn foo() {
/// use arbitrary::{Arbitrary, Unstructured};
///
/// /// An RGB color.
/// #[derive(Arbitrary)]
/// pub struct Rgb {
///     r: u8,
///     g: u8,
///     b: u8,
/// }
///
/// // Get the raw bytes from the fuzzer.
/// #   let get_input_from_fuzzer = || &[];
/// let raw_data: &[u8] = get_input_from_fuzzer();
///
/// // Wrap it in an `Unstructured`.
/// let mut unstructured = Unstructured::new(raw_data);
///
/// // Generate an `Rgb` color and run our checks.
/// if let Ok(rgb) = Rgb::arbitrary(&mut unstructured) {
/// #   let run_my_color_conversion_checks = |_| {};
///     run_my_color_conversion_checks(rgb);
/// }
/// # }
/// ```
pub struct Unstructured<'a> {
    data: &'a [u8],
}

impl<'a> Unstructured<'a> {
    /// Create a new `Unstructured` from the given raw data.
    ///
    /// # Example
    ///
    /// ```
    /// use arbitrary::Unstructured;
    ///
    /// let u = Unstructured::new(&[1, 2, 3, 4]);
    /// ```
    pub fn new(data: &'a [u8]) -> Self {
        Unstructured { data }
    }

    /// Get the number of remaining bytes of underlying data that are still
    /// available.
    ///
    /// # Example
    ///
    /// ```
    /// use arbitrary::{Arbitrary, Unstructured};
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3]);
    ///
    /// // Initially have three bytes of data.
    /// assert_eq!(u.len(), 3);
    ///
    /// // Generating a `bool` consumes one byte from the underlying data, so
    /// // we are left with two bytes afterwards.
    /// let _ = bool::arbitrary(&mut u);
    /// assert_eq!(u.len(), 2);
    /// ```
    #[inline]
    pub fn len(&self) -> usize {
        self.data.len()
    }

    /// Is the underlying unstructured data exhausted?
    ///
    /// `unstructured.is_empty()` is the same as `unstructured.len() == 0`.
    ///
    /// # Example
    ///
    /// ```
    /// use arbitrary::{Arbitrary, Unstructured};
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3, 4]);
    ///
    /// // Initially, we are not empty.
    /// assert!(!u.is_empty());
    ///
    /// // Generating a `u32` consumes all four bytes of the underlying data, so
    /// // we become empty afterwards.
    /// let _ = u32::arbitrary(&mut u);
    /// assert!(u.is_empty());
    /// ```
    #[inline]
    pub fn is_empty(&self) -> bool {
        self.len() == 0
    }

    /// Generate an arbitrary instance of `A`.
    ///
    /// This is simply a helper method that is equivalent to `<A as
    /// Arbitrary>::arbitrary(self)`. This helper is a little bit more concise,
    /// and can be used in situations where Rust's type inference will figure
    /// out what `A` should be.
    ///
    /// # Example
    ///
    /// ```
    /// # #[cfg(feature="derive")] fn foo() -> arbitrary::Result<()> {
    /// use arbitrary::{Arbitrary, Unstructured};
    ///
    /// #[derive(Arbitrary)]
    /// struct MyType {
    ///     // ...
    /// }
    ///
    /// fn do_stuff(value: MyType) {
    /// #   let _ = value;
    ///     // ...
    /// }
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3, 4]);
    ///
    /// // Rust's type inference can figure out that `value` should be of type
    /// // `MyType` here:
    /// let value = u.arbitrary()?;
    /// do_stuff(value);
    /// # Ok(()) }
    /// ```
    pub fn arbitrary<A>(&mut self) -> Result<A>
    where
        A: Arbitrary<'a>,
    {
        <A as Arbitrary<'a>>::arbitrary(self)
    }

    /// Get the number of elements to insert when building up a collection of
    /// arbitrary `ElementType`s.
    ///
    /// This uses the [`<ElementType as
    /// Arbitrary>::size_hint`][crate::Arbitrary::size_hint] method to smartly
    /// choose a length such that we most likely have enough underlying bytes to
    /// construct that many arbitrary `ElementType`s.
    ///
    /// This should only be called within an `Arbitrary` implementation.
    ///
    /// # Example
    ///
    /// ```
    /// use arbitrary::{Arbitrary, Result, Unstructured};
    /// # pub struct MyCollection<T> { _t: std::marker::PhantomData<T> }
    /// # impl<T> MyCollection<T> {
    /// #     pub fn with_capacity(capacity: usize) -> Self { MyCollection { _t: std::marker::PhantomData } }
    /// #     pub fn insert(&mut self, element: T) {}
    /// # }
    ///
    /// impl<'a, T> Arbitrary<'a> for MyCollection<T>
    /// where
    ///     T: Arbitrary<'a>,
    /// {
    ///     fn arbitrary(u: &mut Unstructured<'a>) -> Result<Self> {
    ///         // Get the number of `T`s we should insert into our collection.
    ///         let len = u.arbitrary_len::<T>()?;
    ///
    ///         // And then create a collection of that length!
    ///         let mut my_collection = MyCollection::with_capacity(len);
    ///         for _ in 0..len {
    ///             let element = T::arbitrary(u)?;
    ///             my_collection.insert(element);
    ///         }
    ///
    ///         Ok(my_collection)
    ///     }
    /// }
    /// ```
    pub fn arbitrary_len<ElementType>(&mut self) -> Result<usize>
    where
        ElementType: Arbitrary<'a>,
    {
        let byte_size = self.arbitrary_byte_size()?;
        let (lower, upper) = <ElementType as Arbitrary>::size_hint(0);
        let elem_size = upper.unwrap_or(lower * 2);
        let elem_size = std::cmp::max(1, elem_size);
        Ok(byte_size / elem_size)
    }

    fn arbitrary_byte_size(&mut self) -> Result<usize> {
        if self.data.is_empty() {
            Ok(0)
        } else if self.data.len() == 1 {
            self.data = &[];
            Ok(0)
        } else {
            // Take lengths from the end of the data, since the `libFuzzer` folks
            // found that this lets fuzzers more efficiently explore the input
            // space.
            //
            // https://github.com/rust-fuzz/libfuzzer-sys/blob/0c450753/libfuzzer/utils/FuzzedDataProvider.h#L92-L97

            // We only consume as many bytes as necessary to cover the entire
            // range of the byte string.
            // Note: We cast to u64 so we don't overflow when checking std::u32::MAX + 4 on 32-bit archs
            let len = if self.data.len() as u64 <= std::u8::MAX as u64 + 1 {
                let bytes = 1;
                let max_size = self.data.len() - bytes;
                let (rest, for_size) = self.data.split_at(max_size);
                self.data = rest;
                Self::int_in_range_impl(0..=max_size as u8, for_size.iter().copied())?.0 as usize
            } else if self.data.len() as u64 <= std::u16::MAX as u64 + 2 {
                let bytes = 2;
                let max_size = self.data.len() - bytes;
                let (rest, for_size) = self.data.split_at(max_size);
                self.data = rest;
                Self::int_in_range_impl(0..=max_size as u16, for_size.iter().copied())?.0 as usize
            } else if self.data.len() as u64 <= std::u32::MAX as u64 + 4 {
                let bytes = 4;
                let max_size = self.data.len() - bytes;
                let (rest, for_size) = self.data.split_at(max_size);
                self.data = rest;
                Self::int_in_range_impl(0..=max_size as u32, for_size.iter().copied())?.0 as usize
            } else {
                let bytes = 8;
                let max_size = self.data.len() - bytes;
                let (rest, for_size) = self.data.split_at(max_size);
                self.data = rest;
                Self::int_in_range_impl(0..=max_size as u64, for_size.iter().copied())?.0 as usize
            };

            Ok(len)
        }
    }

    /// Generate an integer within the given range.
    ///
    /// Do not use this to generate the size of a collection. Use
    /// `arbitrary_len` instead.
    ///
    /// # Panics
    ///
    /// Panics if `range.start > range.end`. That is, the given range must be
    /// non-empty.
    ///
    /// # Example
    ///
    /// ```
    /// use arbitrary::{Arbitrary, Unstructured};
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3, 4]);
    ///
    /// let x: i32 = u.int_in_range(-5_000..=-1_000)
    ///     .expect("constructed `u` with enough bytes to generate an `i32`");
    ///
    /// assert!(-5_000 <= x);
    /// assert!(x <= -1_000);
    /// ```
    pub fn int_in_range<T>(&mut self, range: ops::RangeInclusive<T>) -> Result<T>
    where
        T: Int,
    {
        let (result, bytes_consumed) = Self::int_in_range_impl(range, self.data.iter().cloned())?;
        self.data = &self.data[bytes_consumed..];
        Ok(result)
    }

    fn int_in_range_impl<T>(
        range: ops::RangeInclusive<T>,
        mut bytes: impl Iterator<Item = u8>,
    ) -> Result<(T, usize)>
    where
        T: Int,
    {
        let start = *range.start();
        let end = *range.end();
        assert!(
            start <= end,
            "`arbitrary::Unstructured::int_in_range` requires a non-empty range"
        );

        // When there is only one possible choice, don't waste any entropy from
        // the underlying data.
        if start == end {
            return Ok((start, 0));
        }

        // From here on out we work with the unsigned representation. All of the
        // operations performed below work out just as well whether or not `T`
        // is a signed or unsigned integer.
        let start = start.to_unsigned();
        let end = end.to_unsigned();

        let delta = end.wrapping_sub(start);
        debug_assert_ne!(delta, T::Unsigned::ZERO);

        // Compute an arbitrary integer offset from the start of the range. We
        // do this by consuming `size_of(T)` bytes from the input to create an
        // arbitrary integer and then clamping that int into our range bounds
        // with a modulo operation.
        let mut arbitrary_int = T::Unsigned::ZERO;
        let mut bytes_consumed: usize = 0;

        while (bytes_consumed < mem::size_of::<T>())
            && (delta >> T::Unsigned::from_usize(bytes_consumed * 8)) > T::Unsigned::ZERO
        {
            let byte = match bytes.next() {
                None => break,
                Some(b) => b,
            };
            bytes_consumed += 1;

            // Combine this byte into our arbitrary integer, but avoid
            // overflowing the shift for `u8` and `i8`.
            arbitrary_int = if mem::size_of::<T>() == 1 {
                T::Unsigned::from_u8(byte)
            } else {
                (arbitrary_int << 8) | T::Unsigned::from_u8(byte)
            };
        }

        let offset = if delta == T::Unsigned::MAX {
            arbitrary_int
        } else {
            arbitrary_int % (delta.checked_add(T::Unsigned::ONE).unwrap())
        };

        // Finally, we add `start` to our offset from `start` to get the result
        // actual value within the range.
        let result = start.wrapping_add(offset);

        // And convert back to our maybe-signed representation.
        let result = T::from_unsigned(result);
        debug_assert!(*range.start() <= result);
        debug_assert!(result <= *range.end());

        Ok((result, bytes_consumed))
    }

    /// Choose one of the given choices.
    ///
    /// This should only be used inside of `Arbitrary` implementations.
    ///
    /// Returns an error if there is not enough underlying data to make a
    /// choice or if no choices are provided.
    ///
    /// # Examples
    ///
    /// Selecting from an array of choices:
    ///
    /// ```
    /// use arbitrary::Unstructured;
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]);
    /// let choices = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];
    ///
    /// let choice = u.choose(&choices).unwrap();
    ///
    /// println!("chose {}", choice);
    /// ```
    ///
    /// An error is returned if no choices are provided:
    ///
    /// ```
    /// use arbitrary::Unstructured;
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]);
    /// let choices: [char; 0] = [];
    ///
    /// let result = u.choose(&choices);
    ///
    /// assert!(result.is_err());
    /// ```
    pub fn choose<'b, T>(&mut self, choices: &'b [T]) -> Result<&'b T> {
        let idx = self.choose_index(choices.len())?;
        Ok(&choices[idx])
    }

    /// Choose a value in `0..len`.
    ///
    /// Returns an error if the `len` is zero.
    ///
    /// # Examples
    ///
    /// Using Fisher–Yates shuffle shuffle to gerate an arbitrary permutation.
    ///
    /// [Fisher–Yates shuffle]: https://en.wikipedia.org/wiki/Fisher–Yates_shuffle
    ///
    /// ```
    /// use arbitrary::Unstructured;
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]);
    /// let mut permutation = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];
    /// let mut to_permute = &mut permutation[..];
    /// while to_permute.len() > 1 {
    ///     let idx = u.choose_index(to_permute.len()).unwrap();
    ///     to_permute.swap(0, idx);
    ///     to_permute = &mut to_permute[1..];
    /// }
    ///
    /// println!("permutation: {:?}", permutation);
    /// ```
    ///
    /// An error is returned if the length is zero:
    ///
    /// ```
    /// use arbitrary::Unstructured;
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]);
    /// let array: [i32; 0] = [];
    ///
    /// let result = u.choose_index(array.len());
    ///
    /// assert!(result.is_err());
    /// ```
    pub fn choose_index(&mut self, len: usize) -> Result<usize> {
        if len == 0 {
            return Err(Error::EmptyChoose);
        }
        let idx = self.int_in_range(0..=len - 1)?;
        Ok(idx)
    }

    /// Generate a boolean according to the given ratio.
    ///
    /// # Panics
    ///
    /// Panics when the numerator and denominator do not meet these constraints:
    ///
    /// * `0 < numerator <= denominator`
    ///
    /// # Example
    ///
    /// Generate a boolean that is `true` five sevenths of the time:
    ///
    /// ```
    /// # fn foo() -> arbitrary::Result<()> {
    /// use arbitrary::Unstructured;
    ///
    /// # let my_data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0];
    /// let mut u = Unstructured::new(&my_data);
    ///
    /// if u.ratio(5, 7)? {
    ///     // Take this branch 5/7 of the time.
    /// }
    /// # Ok(())
    /// # }
    /// ```
    pub fn ratio<T>(&mut self, numerator: T, denominator: T) -> Result<bool>
    where
        T: Int,
    {
        assert!(T::ZERO < numerator);
        assert!(numerator <= denominator);
        let x = self.int_in_range(T::ONE..=denominator)?;
        Ok(x <= numerator)
    }

    /// Fill a `buffer` with bytes from the underlying raw data.
    ///
    /// This should only be called within an `Arbitrary` implementation. This is
    /// a very low-level operation. You should generally prefer calling nested
    /// `Arbitrary` implementations like `<Vec<u8>>::arbitrary` and
    /// `String::arbitrary` over using this method directly.
    ///
    /// If this `Unstructured` does not have enough underlying data to fill the
    /// whole `buffer`, it pads the buffer out with zeros.
    ///
    /// # Example
    ///
    /// ```
    /// use arbitrary::Unstructured;
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3, 4]);
    ///
    /// let mut buf = [0; 2];
    ///
    /// assert!(u.fill_buffer(&mut buf).is_ok());
    /// assert_eq!(buf, [1, 2]);
    ///
    /// assert!(u.fill_buffer(&mut buf).is_ok());
    /// assert_eq!(buf, [3, 4]);
    ///
    /// assert!(u.fill_buffer(&mut buf).is_ok());
    /// assert_eq!(buf, [0, 0]);
    /// ```
    pub fn fill_buffer(&mut self, buffer: &mut [u8]) -> Result<()> {
        let n = std::cmp::min(buffer.len(), self.data.len());
        buffer[..n].copy_from_slice(&self.data[..n]);
        for byte in buffer[n..].iter_mut() {
            *byte = 0;
        }
        self.data = &self.data[n..];
        Ok(())
    }

    /// Provide `size` bytes from the underlying raw data.
    ///
    /// This should only be called within an `Arbitrary` implementation. This is
    /// a very low-level operation. You should generally prefer calling nested
    /// `Arbitrary` implementations like `<Vec<u8>>::arbitrary` and
    /// `String::arbitrary` over using this method directly.
    ///
    /// # Example
    ///
    /// ```
    /// use arbitrary::Unstructured;
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3, 4]);
    ///
    /// assert!(u.bytes(2).unwrap() == &[1, 2]);
    /// assert!(u.bytes(2).unwrap() == &[3, 4]);
    /// ```
    pub fn bytes(&mut self, size: usize) -> Result<&'a [u8]> {
        if self.data.len() < size {
            return Err(Error::NotEnoughData);
        }

        let (for_buf, rest) = self.data.split_at(size);
        self.data = rest;
        Ok(for_buf)
    }

    /// Peek at `size` number of bytes of the underlying raw input.
    ///
    /// Does not consume the bytes, only peeks at them.
    ///
    /// Returns `None` if there are not `size` bytes left in the underlying raw
    /// input.
    ///
    /// # Example
    ///
    /// ```
    /// use arbitrary::Unstructured;
    ///
    /// let u = Unstructured::new(&[1, 2, 3]);
    ///
    /// assert_eq!(u.peek_bytes(0).unwrap(), []);
    /// assert_eq!(u.peek_bytes(1).unwrap(), [1]);
    /// assert_eq!(u.peek_bytes(2).unwrap(), [1, 2]);
    /// assert_eq!(u.peek_bytes(3).unwrap(), [1, 2, 3]);
    ///
    /// assert!(u.peek_bytes(4).is_none());
    /// ```
    pub fn peek_bytes(&self, size: usize) -> Option<&'a [u8]> {
        self.data.get(..size)
    }

    /// Consume all of the rest of the remaining underlying bytes.
    ///
    /// Returns a slice of all the remaining, unconsumed bytes.
    ///
    /// # Example
    ///
    /// ```
    /// use arbitrary::Unstructured;
    ///
    /// let mut u = Unstructured::new(&[1, 2, 3]);
    ///
    /// let mut remaining = u.take_rest();
    ///
    /// assert_eq!(remaining, [1, 2, 3]);
    /// ```
    pub fn take_rest(mut self) -> &'a [u8] {
        mem::take(&mut self.data)
    }

    /// Provide an iterator over elements for constructing a collection
    ///
    /// This is useful for implementing [`Arbitrary::arbitrary`] on collections
    /// since the implementation is simply `u.arbitrary_iter()?.collect()`
    pub fn arbitrary_iter<'b, ElementType: Arbitrary<'a>>(
        &'b mut self,
    ) -> Result<ArbitraryIter<'a, 'b, ElementType>> {
        Ok(ArbitraryIter {
            u: &mut *self,
            _marker: PhantomData,
        })
    }

    /// Provide an iterator over elements for constructing a collection from
    /// all the remaining bytes.
    ///
    /// This is useful for implementing [`Arbitrary::arbitrary_take_rest`] on collections
    /// since the implementation is simply `u.arbitrary_take_rest_iter()?.collect()`
    pub fn arbitrary_take_rest_iter<ElementType: Arbitrary<'a>>(
        self,
    ) -> Result<ArbitraryTakeRestIter<'a, ElementType>> {
        Ok(ArbitraryTakeRestIter {
            u: self,
            _marker: PhantomData,
        })
    }

    /// Call the given function an arbitrary number of times.
    ///
    /// The function is given this `Unstructured` so that it can continue to
    /// generate arbitrary data and structures.
    ///
    /// You may optionaly specify minimum and maximum bounds on the number of
    /// times the function is called.
    ///
    /// You may break out of the loop early by returning
    /// `Ok(std::ops::ControlFlow::Break)`. To continue the loop, return
    /// `Ok(std::ops::ControlFlow::Continue)`.
    ///
    /// # Panics
    ///
    /// Panics if `min > max`.
    ///
    /// # Example
    ///
    /// Call a closure that generates an arbitrary type inside a context an
    /// arbitrary number of times:
    ///
    /// ```
    /// use arbitrary::{Result, Unstructured};
    /// use std::ops::ControlFlow;
    ///
    /// enum Type {
    ///     /// A boolean type.
    ///     Bool,
    ///
    ///     /// An integer type.
    ///     Int,
    ///
    ///     /// A list of the `i`th type in this type's context.
    ///     List(usize),
    /// }
    ///
    /// fn arbitrary_types_context(u: &mut Unstructured) -> Result<Vec<Type>> {
    ///     let mut context = vec![];
    ///
    ///     u.arbitrary_loop(Some(10), Some(20), |u| {
    ///         let num_choices = if context.is_empty() {
    ///             2
    ///         } else {
    ///             3
    ///         };
    ///         let ty = match u.int_in_range::<u8>(1..=num_choices)? {
    ///             1 => Type::Bool,
    ///             2 => Type::Int,
    ///             3 => Type::List(u.int_in_range(0..=context.len() - 1)?),
    ///             _ => unreachable!(),
    ///         };
    ///         context.push(ty);
    ///         Ok(ControlFlow::Continue(()))
    ///     })?;
    ///
    ///     // The number of loop iterations are constrained by the min/max
    ///     // bounds that we provided.
    ///     assert!(context.len() >= 10);
    ///     assert!(context.len() <= 20);
    ///
    ///     Ok(context)
    /// }
    /// ```
    pub fn arbitrary_loop(
        &mut self,
        min: Option<u32>,
        max: Option<u32>,
        mut f: impl FnMut(&mut Self) -> Result<ControlFlow<(), ()>>,
    ) -> Result<()> {
        let min = min.unwrap_or(0);
        let max = max.unwrap_or(u32::MAX);

        for _ in 0..self.int_in_range(min..=max)? {
            match f(self)? {
                ControlFlow::Continue(_) => continue,
                ControlFlow::Break(_) => break,
            }
        }

        Ok(())
    }
}

/// Utility iterator produced by [`Unstructured::arbitrary_iter`]
pub struct ArbitraryIter<'a, 'b, ElementType> {
    u: &'b mut Unstructured<'a>,
    _marker: PhantomData<ElementType>,
}

impl<'a, 'b, ElementType: Arbitrary<'a>> Iterator for ArbitraryIter<'a, 'b, ElementType> {
    type Item = Result<ElementType>;
    fn next(&mut self) -> Option<Result<ElementType>> {
        let keep_going = self.u.arbitrary().unwrap_or(false);
        if keep_going {
            Some(Arbitrary::arbitrary(self.u))
        } else {
            None
        }
    }
}

/// Utility iterator produced by [`Unstructured::arbitrary_take_rest_iter`]
pub struct ArbitraryTakeRestIter<'a, ElementType> {
    u: Unstructured<'a>,
    _marker: PhantomData<ElementType>,
}

impl<'a, ElementType: Arbitrary<'a>> Iterator for ArbitraryTakeRestIter<'a, ElementType> {
    type Item = Result<ElementType>;
    fn next(&mut self) -> Option<Result<ElementType>> {
        let keep_going = self.u.arbitrary().unwrap_or(false);
        if keep_going {
            Some(Arbitrary::arbitrary(&mut self.u))
        } else {
            None
        }
    }
}

/// A trait that is implemented for all of the primitive integers:
///
/// * `u8`
/// * `u16`
/// * `u32`
/// * `u64`
/// * `u128`
/// * `usize`
/// * `i8`
/// * `i16`
/// * `i32`
/// * `i64`
/// * `i128`
/// * `isize`
///
/// Don't implement this trait yourself.
pub trait Int:
    Copy
    + std::fmt::Debug
    + PartialOrd
    + Ord
    + ops::Sub<Self, Output = Self>
    + ops::Rem<Self, Output = Self>
    + ops::Shr<Self, Output = Self>
    + ops::Shl<usize, Output = Self>
    + ops::BitOr<Self, Output = Self>
{
    #[doc(hidden)]
    type Unsigned: Int;

    #[doc(hidden)]
    const ZERO: Self;

    #[doc(hidden)]
    const ONE: Self;

    #[doc(hidden)]
    const MAX: Self;

    #[doc(hidden)]
    fn from_u8(b: u8) -> Self;

    #[doc(hidden)]
    fn from_usize(u: usize) -> Self;

    #[doc(hidden)]
    fn checked_add(self, rhs: Self) -> Option<Self>;

    #[doc(hidden)]
    fn wrapping_add(self, rhs: Self) -> Self;

    #[doc(hidden)]
    fn wrapping_sub(self, rhs: Self) -> Self;

    #[doc(hidden)]
    fn to_unsigned(self) -> Self::Unsigned;

    #[doc(hidden)]
    fn from_unsigned(unsigned: Self::Unsigned) -> Self;
}

macro_rules! impl_int {
    ( $( $ty:ty : $unsigned_ty: ty ; )* ) => {
        $(
            impl Int for $ty {
                type Unsigned = $unsigned_ty;

                const ZERO: Self = 0;

                const ONE: Self = 1;

                const MAX: Self = Self::MAX;

                fn from_u8(b: u8) -> Self {
                    b as Self
                }

                fn from_usize(u: usize) -> Self {
                    u as Self
                }

                fn checked_add(self, rhs: Self) -> Option<Self> {
                    <$ty>::checked_add(self, rhs)
                }

                fn wrapping_add(self, rhs: Self) -> Self {
                    <$ty>::wrapping_add(self, rhs)
                }

                fn wrapping_sub(self, rhs: Self) -> Self {
                    <$ty>::wrapping_sub(self, rhs)
                }

                fn to_unsigned(self) -> Self::Unsigned {
                    self as $unsigned_ty
                }

                fn from_unsigned(unsigned: $unsigned_ty) -> Self {
                    unsigned as Self
                }
            }
        )*
    }
}

impl_int! {
    u8: u8;
    u16: u16;
    u32: u32;
    u64: u64;
    u128: u128;
    usize: usize;
    i8: u8;
    i16: u16;
    i32: u32;
    i64: u64;
    i128: u128;
    isize: usize;
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_byte_size() {
        let mut u = Unstructured::new(&[1, 2, 3, 4, 5, 6, 7, 8, 9, 6]);
        // Should take one byte off the end
        assert_eq!(u.arbitrary_byte_size().unwrap(), 6);
        assert_eq!(u.len(), 9);
        let mut v = vec![];
        v.resize(260, 0);
        v.push(1);
        v.push(4);
        let mut u = Unstructured::new(&v);
        // Should read two bytes off the end
        assert_eq!(u.arbitrary_byte_size().unwrap(), 0x104);
        assert_eq!(u.len(), 260);
    }

    #[test]
    fn int_in_range_of_one() {
        let mut u = Unstructured::new(&[1, 2, 3, 4, 5, 6, 7, 8, 9, 6]);
        let x = u.int_in_range(0..=0).unwrap();
        assert_eq!(x, 0);
        let choice = *u.choose(&[42]).unwrap();
        assert_eq!(choice, 42)
    }

    #[test]
    fn int_in_range_uses_minimal_amount_of_bytes() {
        let mut u = Unstructured::new(&[1, 2]);
        assert_eq!(1, u.int_in_range::<u8>(0..=u8::MAX).unwrap());
        assert_eq!(u.len(), 1);

        let mut u = Unstructured::new(&[1, 2]);
        assert_eq!(1, u.int_in_range::<u32>(0..=u8::MAX as u32).unwrap());
        assert_eq!(u.len(), 1);

        let mut u = Unstructured::new(&[1]);
        assert_eq!(1, u.int_in_range::<u32>(0..=u8::MAX as u32 + 1).unwrap());
        assert!(u.is_empty());
    }

    #[test]
    fn int_in_range_in_bounds() {
        for input in u8::MIN..=u8::MAX {
            let input = [input];

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(1..=u8::MAX).unwrap();
            assert_ne!(x, 0);

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(0..=u8::MAX - 1).unwrap();
            assert_ne!(x, u8::MAX);
        }
    }

    #[test]
    fn int_in_range_covers_unsigned_range() {
        // Test that we generate all values within the range given to
        // `int_in_range`.

        let mut full = [false; u8::MAX as usize + 1];
        let mut no_zero = [false; u8::MAX as usize];
        let mut no_max = [false; u8::MAX as usize];
        let mut narrow = [false; 10];

        for input in u8::MIN..=u8::MAX {
            let input = [input];

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(0..=u8::MAX).unwrap();
            full[x as usize] = true;

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(1..=u8::MAX).unwrap();
            no_zero[x as usize - 1] = true;

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(0..=u8::MAX - 1).unwrap();
            no_max[x as usize] = true;

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(100..=109).unwrap();
            narrow[x as usize - 100] = true;
        }

        for (i, covered) in full.iter().enumerate() {
            assert!(covered, "full[{}] should have been generated", i);
        }
        for (i, covered) in no_zero.iter().enumerate() {
            assert!(covered, "no_zero[{}] should have been generated", i);
        }
        for (i, covered) in no_max.iter().enumerate() {
            assert!(covered, "no_max[{}] should have been generated", i);
        }
        for (i, covered) in narrow.iter().enumerate() {
            assert!(covered, "narrow[{}] should have been generated", i);
        }
    }

    #[test]
    fn int_in_range_covers_signed_range() {
        // Test that we generate all values within the range given to
        // `int_in_range`.

        let mut full = [false; u8::MAX as usize + 1];
        let mut no_min = [false; u8::MAX as usize];
        let mut no_max = [false; u8::MAX as usize];
        let mut narrow = [false; 21];

        let abs_i8_min: isize = 128;

        for input in 0..=u8::MAX {
            let input = [input];

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(i8::MIN..=i8::MAX).unwrap();
            full[(x as isize + abs_i8_min) as usize] = true;

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(i8::MIN + 1..=i8::MAX).unwrap();
            no_min[(x as isize + abs_i8_min - 1) as usize] = true;

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(i8::MIN..=i8::MAX - 1).unwrap();
            no_max[(x as isize + abs_i8_min) as usize] = true;

            let mut u = Unstructured::new(&input);
            let x = u.int_in_range(-10..=10).unwrap();
            narrow[(x as isize + 10) as usize] = true;
        }

        for (i, covered) in full.iter().enumerate() {
            assert!(covered, "full[{}] should have been generated", i);
        }
        for (i, covered) in no_min.iter().enumerate() {
            assert!(covered, "no_min[{}] should have been generated", i);
        }
        for (i, covered) in no_max.iter().enumerate() {
            assert!(covered, "no_max[{}] should have been generated", i);
        }
        for (i, covered) in narrow.iter().enumerate() {
            assert!(covered, "narrow[{}] should have been generated", i);
        }
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/flagset-0.4.5/src/lib.rs

Source (jump to first uncovered line)
//
// Copyright 2019 Red Hat, Inc.
//
// Author: Nathaniel McCallum <npmccallum@redhat.com>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

//! # Welcome to FlagSet!
//!
//! FlagSet is a new, ergonomic approach to handling flags that combines the
//! best of existing crates like `bitflags` and `enumflags` without their
//! downsides.
//!
//! ## Existing Implementations
//!
//! The `bitflags` crate has long been part of the Rust ecosystem.
//! Unfortunately, it doesn't feel like natural Rust. The `bitflags` crate
//! uses a wierd struct format to define flags. Flags themselves are just
//! integers constants, so there is little type-safety involved. But it doesn't
//! have any dependencies. It also allows you to define implied flags (otherwise
//! known as overlapping flags).
//!
//! The `enumflags` crate tried to improve on `bitflags` by using enumerations
//! to define flags. This was a big improvement to the natural feel of the code.
//! Unfortunately, there are some design flaws. To generate the flags,
//! procedural macros were used. This implied two separate crates plus
//! additional dependencies. Further, `enumflags` specifies the size of the
//! flags using a `repr($size)` attribute. Unfortunately, this attribute
//! cannot resolve type aliases, such as `c_int`. This makes `enumflags` a
//! poor fit for FFI, which is the most important place for a flags library.
//! The `enumflags` crate also disallows overlapping flags and is not
//! maintained.
//!
//! FlagSet improves on both of these by adopting the `enumflags` natural feel
//! and the `bitflags` mode of flag generation; as well as additional API usage
//! niceties. FlagSet has no dependencies and is extensively documented and
//! tested. It also tries very hard to prevent you from making mistakes by
//! avoiding external usage of the integer types. FlagSet is also a zero-cost
//! abstraction: all functions are inlineable and should reduce to the core
//! integer operations. FlagSet also does not depend on stdlib, so it can be
//! used in `no_std` libraries and applications.
//!
//! ## Defining Flags
//!
//! Flags are defined using the `flags!` macro:
//!
//! ```
//! use flagset::{FlagSet, flags};
//! use std::os::raw::c_int;
//!
//! flags! {
//!     enum FlagsA: u8 {
//!         Foo,
//!         Bar,
//!         Baz,
//!     }
//!
//!     enum FlagsB: c_int {
//!         Foo,
//!         Bar,
//!         Baz,
//!     }
//! }
//! ```
//!
//! Notice that a flag definition looks just like a regular enumeration, with
//! the addition of the field-size type. The field-size type is required and
//! can be either a type or a type alias. Both examples are given above.
//!
//! Also note that the field-size type specifies the size of the corresponding
//! `FlagSet` type, not size of the enumeration itself. To specify the size of
//! the enumeration, use the `repr($size)` attribute as specified below.
//!
//! ## Flag Values
//!
//! Flags often need values assigned to them. This can be done implicitly,
//! where the value depends on the order of the flags:
//!
//! ```
//! use flagset::{FlagSet, flags};
//!
//! flags! {
//!     enum Flags: u16 {
//!         Foo, // Implicit Value: 0b0001
//!         Bar, // Implicit Value: 0b0010
//!         Baz, // Implicit Value: 0b0100
//!     }
//! }
//! ```
//!
//! Alternatively, flag values can be defined explicitly, by specifying any
//! `const` expression:
//!
//! ```
//! use flagset::{FlagSet, flags};
//!
//! flags! {
//!     enum Flags: u16 {
//!         Foo = 0x01,   // Explicit Value: 0b0001
//!         Bar = 2,      // Explicit Value: 0b0010
//!         Baz = 0b0100, // Explicit Value: 0b0100
//!     }
//! }
//! ```
//!
//! Flags can also overlap or "imply" other flags:
//!
//! ```
//! use flagset::{FlagSet, flags};
//!
//! flags! {
//!     enum Flags: u16 {
//!         Foo = 0b0001,
//!         Bar = 0b0010,
//!         Baz = 0b0110, // Implies Bar
//!         All = (Flags::Foo | Flags::Bar | Flags::Baz).bits(),
//!     }
//! }
//! ```
//!
//! ## Specifying Attributes
//!
//! Attributes can be used on the enumeration itself or any of the values:
//!
//! ```
//! use flagset::{FlagSet, flags};
//!
//! flags! {
//!     #[derive(PartialOrd, Ord)]
//!     enum Flags: u8 {
//!         Foo,
//!         #[deprecated]
//!         Bar,
//!         Baz,
//!     }
//! }
//! ```
//!
//! ## Collections of Flags
//!
//! A collection of flags is a `FlagSet<T>`. If you are storing the flags in
//! memory, the raw `FlagSet<T>` type should be used. However, if you want to
//! receive flags as an input to a function, you should use
//! `impl Into<FlagSet<T>>`. This allows for very ergonomic APIs:
//!
//! ```
//! use flagset::{FlagSet, flags};
//!
//! flags! {
//!     enum Flags: u8 {
//!         Foo,
//!         Bar,
//!         Baz,
//!     }
//! }
//!
//! struct Container(FlagSet<Flags>);
//!
//! impl Container {
//!     fn new(flags: impl Into<FlagSet<Flags>>) -> Container {
//!         Container(flags.into())
//!     }
//! }
//!
//! assert_eq!(Container::new(Flags::Foo | Flags::Bar).0.bits(), 0b011);
//! assert_eq!(Container::new(Flags::Foo).0.bits(), 0b001);
//! assert_eq!(Container::new(None).0.bits(), 0b000);
//! ```
//!
//! ## Operations
//!
//! Operations can be performed on a `FlagSet<F>` or on individual flags:
//!
//! | Operator | Assignment Operator | Meaning                |
//! |----------|---------------------|------------------------|
//! | \|       | \|=                 | Union                  |
//! | &        | &=                  | Intersection           |
//! | ^        | ^=                  | Toggle specified flags |
//! | -        | -=                  | Difference             |
//! | %        | %=                  | Symmetric difference   |
//! | !        |                     | Toggle all flags       |
//!
#![cfg_attr(
    feature = "serde",
    doc = r#"

## Optional Serde support

[Serde] support can be enabled with the 'serde' feature flag. You can then serialize and
deserialize `FlagSet<T>` to and from any of the [supported formats]:

 ```
 use flagset::{FlagSet, flags};

 flags! {
     enum Flags: u8 {
         Foo,
         Bar,
     }
 }

 let flagset = Flags::Foo | Flags::Bar;
 let json = serde_json::to_string(&flagset).unwrap();
 let flagset: FlagSet<Flags> = serde_json::from_str(&json).unwrap();
 assert_eq!(flagset.bits(), 0b011);
 ```

For serialization and deserialization of flags enum itself, you can use the [`serde_repr`] crate
(or implement `serde::ser::Serialize` and `serde:de::Deserialize` manually), combined with the
appropriate `repr` attribute:

 ```
 use flagset::{FlagSet, flags};
 use serde_repr::{Serialize_repr, Deserialize_repr};

 flags! {
    #[repr(u8)]
    #[derive(Deserialize_repr, Serialize_repr)]
    enum Flags: u8 {
         Foo,
         Bar,
    }
 }

 let json = serde_json::to_string(&Flags::Foo).unwrap();
 let flag: Flags = serde_json::from_str(&json).unwrap();
 assert_eq!(flag, Flags::Foo);
 ```

[Serde]: https://serde.rs/
[supported formats]: https://serde.rs/#data-formats
[`serde_repr`]: https://crates.io/crates/serde_repr
"#
)]
#![allow(unknown_lints)]
#![warn(clippy::all)]
#![cfg_attr(not(feature = "std"), no_std)]
#![cfg_attr(docsrs, feature(doc_auto_cfg))]

use core::fmt::{Debug, Formatter, Result};
use core::ops::*;

/// Error type returned when creating a new flagset from bits is invalid or undefined.
/// ```
/// use flagset::{FlagSet, flags};
///
/// flags! {
///     pub enum Flag: u16 {
///         Foo = 0b0001,
///         Bar = 0b0010,
///         Baz = 0b0100,
///         Qux = 0b1010, // Implies Bar
///     }
/// }
///
/// assert_eq!(FlagSet::<Flag>::new(0b01101), Err(flagset::InvalidBits)); // Invalid
/// assert_eq!(FlagSet::<Flag>::new(0b10101), Err(flagset::InvalidBits)); // Unknown
/// ```
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct InvalidBits;

impl core::fmt::Display for InvalidBits {
    #[inline]
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        write!(f, "invalid bits")
    }
}

#[cfg(feature = "std")]
impl std::error::Error for InvalidBits {}

#[doc(hidden)]
pub trait Flags:
    Copy
    + Clone
    + Debug
    + PartialEq
    + Eq
    + BitAnd<Self, Output = FlagSet<Self>>
    + BitOr<Self, Output = FlagSet<Self>>
    + BitXor<Self, Output = FlagSet<Self>>
    + Sub<Self, Output = FlagSet<Self>>
    + Rem<Self, Output = FlagSet<Self>>
    + Not<Output = FlagSet<Self>>
    + Into<FlagSet<Self>>
    + 'static
{
    type Type: Copy
        + Clone
        + Debug
        + PartialEq
        + Eq
        + Default
        + BitAnd<Self::Type, Output = Self::Type>
        + BitAndAssign<Self::Type>
        + BitOr<Self::Type, Output = Self::Type>
        + BitOrAssign<Self::Type>
        + BitXor<Self::Type, Output = Self::Type>
        + BitXorAssign<Self::Type>
        + Not<Output = Self::Type>;

    /// A slice containing all the possible flag values.
    const LIST: &'static [Self];

    /// Creates an empty `FlagSet` of this type
    #[inline]
    fn none() -> FlagSet<Self> {
        FlagSet::default()
    }
}

#[derive(Copy, Clone, Eq, Hash)]
pub struct FlagSet<F: Flags>(F::Type);

#[doc(hidden)]
#[derive(Copy, Clone)]
pub struct Iter<F: Flags>(FlagSet<F>, usize);

impl<F: Flags> Iterator for Iter<F> {
    type Item = F;

    #[inline]
    fn next(&mut self) -> Option<Self::Item> {
        while self.1 < F::LIST.len() {
            let next = F::LIST[self.1];
            self.1 += 1;

            if self.0.contains(next) {
                return Some(next);
            }
        }

        None
    }
}

impl<F: Flags> IntoIterator for FlagSet<F> {
    type Item = F;
    type IntoIter = Iter<F>;

    /// Iterate over the flags in the set.
    ///
    /// **NOTE**: The order in which the flags are iterated is undefined.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     enum Flag: u8 {
    ///         Foo = 0b001,
    ///         Bar = 0b010,
    ///         Baz = 0b100
    ///     }
    /// }
    ///
    /// let set = Flag::Foo | Flag::Bar;
    /// let mut iter = set.into_iter();
    /// assert_eq!(iter.next(), Some(Flag::Foo));
    /// assert_eq!(iter.next(), Some(Flag::Bar));
    /// assert_eq!(iter.next(), None);
    /// ```
    #[inline]
    fn into_iter(self) -> Self::IntoIter {
        Iter(self, 0)
    }
}

impl<F: Flags> Debug for FlagSet<F> {
    #[inline]
    fn fmt(&self, f: &mut Formatter) -> Result {
        write!(f, "FlagSet(")?;
        for (i, flag) in self.into_iter().enumerate() {
            write!(f, "{}{:?}", if i > 0 { " | " } else { "" }, flag)?;
        }
        write!(f, ")")
    }
}

impl<F: Flags, R: Copy + Into<FlagSet<F>>> PartialEq<R> for FlagSet<F> {
    #[inline]
    fn eq(&self, rhs: &R) -> bool {
        self.0 == (*rhs).into().0
    }
}

impl<F: Flags> AsRef<F::Type> for FlagSet<F> {
    #[inline]
    fn as_ref(&self) -> &F::Type {
        &self.0
    }
}

impl<F: Flags> From<Option<FlagSet<F>>> for FlagSet<F> {
    /// Converts from `Option<FlagSet<F>>` to `FlagSet<F>`.
    ///
    /// Most notably, this allows for the use of `None` in many places to
    /// substitute for manually creating an empty `FlagSet<F>`. See below.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     enum Flag: u8 {
    ///         Foo = 0b001,
    ///         Bar = 0b010,
    ///         Baz = 0b100
    ///     }
    /// }
    ///
    /// fn convert(v: impl Into<FlagSet<Flag>>) -> u8 {
    ///     v.into().bits()
    /// }
    ///
    /// assert_eq!(convert(Flag::Foo | Flag::Bar), 0b011);
    /// assert_eq!(convert(Flag::Foo), 0b001);
    /// assert_eq!(convert(None), 0b000);
    /// ```
    #[inline]
    fn from(value: Option<FlagSet<F>>) -> FlagSet<F> {
        value.unwrap_or_default()
    }
}

impl<F: Flags> Default for FlagSet<F> {
    /// Creates a new, empty FlagSet.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     enum Flag: u8 {
    ///         Foo = 0b001,
    ///         Bar = 0b010,
    ///         Baz = 0b100
    ///     }
    /// }
    ///
    /// let set = FlagSet::<Flag>::default();
    /// assert!(set.is_empty());
    /// assert!(!set.is_full());
    /// assert!(!set.contains(Flag::Foo));
    /// assert!(!set.contains(Flag::Bar));
    /// assert!(!set.contains(Flag::Baz));
    /// ```
    #[inline]
    fn default() -> Self {
        FlagSet(F::Type::default())
    }
}

impl<F: Flags> Not for FlagSet<F> {
    type Output = Self;

    /// Calculates the complement of the current set.
    ///
    /// In common parlance, this returns the set of all possible flags that are
    /// not in the current set.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     #[derive(PartialOrd, Ord)]
    ///     enum Flag: u8 {
    ///         Foo = 1 << 0,
    ///         Bar = 1 << 1,
    ///         Baz = 1 << 2
    ///     }
    /// }
    ///
    /// let set = !FlagSet::from(Flag::Foo);
    /// assert!(!set.is_empty());
    /// assert!(!set.is_full());
    /// assert!(!set.contains(Flag::Foo));
    /// assert!(set.contains(Flag::Bar));
    /// assert!(set.contains(Flag::Baz));
    /// ```
    #[inline]
    fn not(self) -> Self {
        FlagSet(!self.0)
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> BitAnd<R> for FlagSet<F> {
    type Output = Self;

    /// Calculates the intersection of the current set and the specified flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     #[derive(PartialOrd, Ord)]
    ///     pub enum Flag: u8 {
    ///         Foo = 0b001,
    ///         Bar = 0b010,
    ///         Baz = 0b100
    ///     }
    /// }
    ///
    /// let set0 = Flag::Foo | Flag::Bar;
    /// let set1 = Flag::Baz | Flag::Bar;
    /// assert_eq!(set0 & set1, Flag::Bar);
    /// assert_eq!(set0 & Flag::Foo, Flag::Foo);
    /// assert_eq!(set1 & Flag::Baz, Flag::Baz);
    /// ```
    #[inline]
    fn bitand(self, rhs: R) -> Self {
        FlagSet(self.0 & rhs.into().0)
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> BitAndAssign<R> for FlagSet<F> {
    /// Assigns the intersection of the current set and the specified flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     enum Flag: u64 {
    ///         Foo = 0b001,
    ///         Bar = 0b010,
    ///         Baz = 0b100
    ///     }
    /// }
    ///
    /// let mut set0 = Flag::Foo | Flag::Bar;
    /// let mut set1 = Flag::Baz | Flag::Bar;
    ///
    /// set0 &= set1;
    /// assert_eq!(set0, Flag::Bar);
    ///
    /// set1 &= Flag::Baz;
    /// assert_eq!(set0, Flag::Bar);
    /// ```
    #[inline]
    fn bitand_assign(&mut self, rhs: R) {
        self.0 &= rhs.into().0
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> BitOr<R> for FlagSet<F> {
    type Output = Self;

    /// Calculates the union of the current set with the specified flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     #[derive(PartialOrd, Ord)]
    ///     pub enum Flag: u8 {
    ///         Foo = 0b001,
    ///         Bar = 0b010,
    ///         Baz = 0b100
    ///     }
    /// }
    ///
    /// let set0 = Flag::Foo | Flag::Bar;
    /// let set1 = Flag::Baz | Flag::Bar;
    /// assert_eq!(set0 | set1, FlagSet::full());
    /// ```
    #[inline]
    fn bitor(self, rhs: R) -> Self {
        FlagSet(self.0 | rhs.into().0)
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> BitOrAssign<R> for FlagSet<F> {
    /// Assigns the union of the current set with the specified flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     enum Flag: u64 {
    ///         Foo = 0b001,
    ///         Bar = 0b010,
    ///         Baz = 0b100
    ///     }
    /// }
    ///
    /// let mut set0 = Flag::Foo | Flag::Bar;
    /// let mut set1 = Flag::Bar | Flag::Baz;
    ///
    /// set0 |= set1;
    /// assert_eq!(set0, FlagSet::full());
    ///
    /// set1 |= Flag::Baz;
    /// assert_eq!(set1, Flag::Bar | Flag::Baz);
    /// ```
    #[inline]
    fn bitor_assign(&mut self, rhs: R) {
        self.0 |= rhs.into().0
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> BitXor<R> for FlagSet<F> {
    type Output = Self;

    /// Calculates the current set with the specified flags toggled.
    ///
    /// This is commonly known as toggling the presence
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     enum Flag: u32 {
    ///         Foo = 0b001,
    ///         Bar = 0b010,
    ///         Baz = 0b100
    ///     }
    /// }
    ///
    /// let set0 = Flag::Foo | Flag::Bar;
    /// let set1 = Flag::Baz | Flag::Bar;
    /// assert_eq!(set0 ^ set1, Flag::Foo | Flag::Baz);
    /// assert_eq!(set0 ^ Flag::Foo, Flag::Bar);
    /// ```
    #[inline]
    fn bitxor(self, rhs: R) -> Self {
        FlagSet(self.0 ^ rhs.into().0)
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> BitXorAssign<R> for FlagSet<F> {
    /// Assigns the current set with the specified flags toggled.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     enum Flag: u16 {
    ///         Foo = 0b001,
    ///         Bar = 0b010,
    ///         Baz = 0b100
    ///     }
    /// }
    ///
    /// let mut set0 = Flag::Foo | Flag::Bar;
    /// let mut set1 = Flag::Baz | Flag::Bar;
    ///
    /// set0 ^= set1;
    /// assert_eq!(set0, Flag::Foo | Flag::Baz);
    ///
    /// set1 ^= Flag::Baz;
    /// assert_eq!(set1, Flag::Bar);
    /// ```
    #[inline]
    fn bitxor_assign(&mut self, rhs: R) {
        self.0 ^= rhs.into().0
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> Sub<R> for FlagSet<F> {
    type Output = Self;

    /// Calculates set difference (the current set without the specified flags).
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let set0 = Flag::Foo | Flag::Bar;
    /// let set1 = Flag::Baz | Flag::Bar;
    /// assert_eq!(set0 - set1, Flag::Foo);
    /// ```
    #[inline]
    fn sub(self, rhs: R) -> Self {
        self & !rhs.into()
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> SubAssign<R> for FlagSet<F> {
    /// Assigns set difference (the current set without the specified flags).
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let mut set0 = Flag::Foo | Flag::Bar;
    /// set0 -= Flag::Baz | Flag::Bar;
    /// assert_eq!(set0, Flag::Foo);
    /// ```
    #[inline]
    fn sub_assign(&mut self, rhs: R) {
        *self &= !rhs.into();
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> Rem<R> for FlagSet<F> {
    type Output = Self;

    /// Calculates the symmetric difference between two sets.
    ///
    /// The symmetric difference between two sets is the set of all flags
    /// that appear in one set or the other, but not both.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let set0 = Flag::Foo | Flag::Bar;
    /// let set1 = Flag::Baz | Flag::Bar;
    /// assert_eq!(set0 % set1, Flag::Foo | Flag::Baz);
    /// ```
    #[inline]
    fn rem(self, rhs: R) -> Self {
        let rhs = rhs.into();
        (self - rhs) | (rhs - self)
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> RemAssign<R> for FlagSet<F> {
    /// Assigns the symmetric difference between two sets.
    ///
    /// The symmetric difference between two sets is the set of all flags
    /// that appear in one set or the other, but not both.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let mut set0 = Flag::Foo | Flag::Bar;
    /// let set1 = Flag::Baz | Flag::Bar;
    /// set0 %= set1;
    /// assert_eq!(set0, Flag::Foo | Flag::Baz);
    /// ```
    #[inline]
    fn rem_assign(&mut self, rhs: R) {
        *self = *self % rhs
    }
}

impl<F: Flags, R: Into<FlagSet<F>>> Extend<R> for FlagSet<F> {
    /// Add values by iterating over some collection.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let flag_vec = vec![Flag::Bar, Flag::Baz];
    /// let mut some_extended_flags = FlagSet::from(Flag::Foo);
    /// some_extended_flags.extend(flag_vec);
    /// assert_eq!(some_extended_flags, Flag::Foo | Flag::Bar | Flag::Baz);
    /// ```
    fn extend<T>(&mut self, iter: T)
    where
        T: IntoIterator<Item = R>,
    {
        for item in iter {
            *self |= item;
        }
    }
}

impl<F: Flags> FlagSet<F> {
    /// Creates a new set from bits; returning `Err(InvalidBits)` on invalid/unknown bits.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u16 {
    ///         Foo = 0b0001,
    ///         Bar = 0b0010,
    ///         Baz = 0b0100,
    ///         Qux = 0b1010, // Implies Bar
    ///     }
    /// }
    ///
    /// assert_eq!(FlagSet::<Flag>::new(0b00101), Ok(Flag::Foo | Flag::Baz));
    /// assert_eq!(FlagSet::<Flag>::new(0b01101), Err(flagset::InvalidBits)); // Invalid
    /// assert_eq!(FlagSet::<Flag>::new(0b10101), Err(flagset::InvalidBits)); // Unknown
    /// ```
    #[inline]
    pub fn new(bits: F::Type) -> core::result::Result<Self, InvalidBits> {
        if Self::new_truncated(bits).0 == bits {
            return Ok(FlagSet(bits));
        }

        Err(InvalidBits)
    }

    /// Creates a new set from bits; truncating invalid/unknown bits.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u16 {
    ///         Foo = 0b0001,
    ///         Bar = 0b0010,
    ///         Baz = 0b0100,
    ///         Qux = 0b1010, // Implies Bar
    ///     }
    /// }
    ///
    /// let set = FlagSet::new_truncated(0b11101);  // Has invalid and unknown.
    /// assert_eq!(set, Flag::Foo | Flag::Baz);
    /// assert_eq!(set.bits(), 0b00101);            // Has neither.
    /// ```
    #[inline]
    pub fn new_truncated(bits: F::Type) -> Self {
        let mut set = Self::default();

        for flag in FlagSet::<F>(bits) {
            set |= flag;
        }

        set
    }

    /// Creates a new set from bits; use of invalid/unknown bits is undefined.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u16 {
    ///         Foo = 0b0001,
    ///         Bar = 0b0010,
    ///         Baz = 0b0100,
    ///         Qux = 0b1010, // Implies Bar
    ///     }
    /// }
    ///
    /// // Unknown and invalid bits are retained. Behavior is undefined.
    /// const set: FlagSet<Flag> = unsafe { FlagSet::<Flag>::new_unchecked(0b11101) };
    /// assert_eq!(set.bits(), 0b11101);
    /// ```
    ///
    /// # Safety
    ///
    /// This constructor doesn't check that the bits are valid. If you pass
    /// undefined flags, undefined behavior may result.
    #[inline]
    pub const unsafe fn new_unchecked(bits: F::Type) -> Self {
        FlagSet(bits)
    }

    /// Creates a new FlagSet containing all possible flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let set = FlagSet::full();
    /// assert!(!set.is_empty());
    /// assert!(set.is_full());
    /// assert!(set.contains(Flag::Foo));
    /// assert!(set.contains(Flag::Bar));
    /// assert!(set.contains(Flag::Baz));
    /// ```
    #[inline]
    pub fn full() -> Self {
        let mut set = Self::default();
        for f in F::LIST {
            set |= *f
        }
        set
    }

    /// Returns the raw bits of the set.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u16 {
    ///         Foo = 0b0001,
    ///         Bar = 0b0010,
    ///         Baz = 0b0100,
    ///     }
    /// }
    ///
    /// let set = Flag::Foo | Flag::Baz;
    /// assert_eq!(set.bits(), 0b0101u16);
    /// ```
    #[inline]
    pub fn bits(self) -> F::Type {
        self.0
    }

    /// Returns true if the FlagSet contains no flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let mut set = Flag::Foo | Flag::Bar;
    /// assert!(!set.is_empty());
    ///
    /// set &= Flag::Baz;
    /// assert!(set.is_empty());
    /// ```
    #[inline]
    pub fn is_empty(self) -> bool {
        self == Self::default()
    }

    /// Returns true if the FlagSet contains all possible flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let mut set = Flag::Foo | Flag::Bar;
    /// assert!(!set.is_full());
    ///
    /// set |= Flag::Baz;
    /// assert!(set.is_full());
    /// ```
    #[inline]
    pub fn is_full(self) -> bool {
        self == Self::full()
    }

    /// Returns true if the two `FlagSet`s do not share any flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let set = Flag::Foo | Flag::Bar;
    /// assert!(!set.is_disjoint(Flag::Foo));
    /// assert!(!set.is_disjoint(Flag::Foo | Flag::Baz));
    /// assert!(set.is_disjoint(Flag::Baz));
    /// ```
    #[inline]
    pub fn is_disjoint(self, rhs: impl Into<FlagSet<F>>) -> bool {
        self & rhs == Self::default()
    }

    /// Returns true if this FlagSet is a superset of the specified flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let set = Flag::Foo | Flag::Bar;
    /// assert!(set.contains(Flag::Foo));
    /// assert!(set.contains(Flag::Foo | Flag::Bar));
    /// assert!(!set.contains(Flag::Foo | Flag::Bar | Flag::Baz));
    /// ```
    #[inline]
    pub fn contains(self, rhs: impl Into<FlagSet<F>>) -> bool {
        let rhs = rhs.into();
        self & rhs == rhs
    }

    /// Removes all flags from the FlagSet.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let mut set = Flag::Foo | Flag::Bar;
    /// assert!(!set.is_empty());
    ///
    /// set.clear();
    /// assert!(set.is_empty());
    /// ```
    #[inline]
    pub fn clear(&mut self) {
        *self = Self::default();
    }

    /// Clears the current set and returns an iterator of all removed flags.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let mut set = Flag::Foo | Flag::Bar;
    /// let mut iter = set.drain();
    /// assert!(set.is_empty());
    /// assert_eq!(iter.next(), Some(Flag::Foo));
    /// assert_eq!(iter.next(), Some(Flag::Bar));
    /// assert_eq!(iter.next(), None);
    /// ```
    #[inline]
    pub fn drain(&mut self) -> Iter<F> {
        let iter = self.into_iter();
        *self = Self::default();
        iter
    }

    /// Retain only the flags flags specified by the predicate.
    ///
    /// ```
    /// use flagset::{FlagSet, flags};
    ///
    /// flags! {
    ///     pub enum Flag: u8 {
    ///         Foo = 1,
    ///         Bar = 2,
    ///         Baz = 4
    ///     }
    /// }
    ///
    /// let mut set0 = Flag::Foo | Flag::Bar;
    /// set0.retain(|f| f != Flag::Foo);
    /// assert_eq!(set0, Flag::Bar);
    /// ```
    #[inline]
    pub fn retain(&mut self, func: impl Fn(F) -> bool) {
        for f in self.into_iter() {
            if !func(f) {
                *self -= f
            }
        }
    }
}

#[cfg(feature = "serde")]
impl<F: Flags> serde::Serialize for FlagSet<F>
where
    F::Type: serde::ser::Serialize,
{
    #[inline]
    fn serialize<S>(&self, serializer: S) -> core::result::Result<S::Ok, S::Error>
    where
        S: serde::ser::Serializer,
    {
        self.0.serialize(serializer)
    }
}

#[cfg(feature = "serde")]
impl<'de, F: Flags> serde::Deserialize<'de> for FlagSet<F>
where
    F::Type: serde::de::Deserialize<'de>,
{
    #[inline]
    fn deserialize<D>(deserializer: D) -> core::result::Result<Self, D::Error>
    where
        D: serde::de::Deserializer<'de>,
    {
        Ok(FlagSet(F::Type::deserialize(deserializer)?))
    }
}

/// Define flag value using the `enum` syntax. See below for details.
///
/// Each enumeration value **MUST** have a specified value.
///
/// The width of the bitfield **MUST** also be specified by its integer type.
///
/// It is important to note that the size of the flag enumeration itself is
/// unrelated to the size of the corresponding `FlagSet` instance.
///
/// It is also worth noting that this macro automatically implements a variety
/// of standard traits including:
///   * Copy
///   * Clone
///   * Debug
///   * PartialEq
///   * Eq
///   * From<$enum> for $integer
///   * Not
///   * BitAnd
///   * BitOr
///   * BitXor
///   * Sub
///   * Rem
///
/// ```
/// use std::mem::{align_of, size_of};
/// use flagset::{FlagSet, flags};
///
/// flags! {
///     enum FlagEmpty: u32 {}
///
///     enum Flag8: u8 {
///         Foo = 0b001,
///         Bar = 0b010,
///         Baz = 0b100
///     }
///
///     pub enum Flag16: u16 {
///         Foo,
///         Bar,
///         #[deprecated]
///         Baz,
///     }
///
///     #[derive(PartialOrd, Ord)]
///     enum Flag32: u32 {
///         Foo = 0b001,
///         #[deprecated]
///         Bar = 0b010,
///         Baz = 0b100
///     }
///
///     #[repr(u64)]
///     enum Flag64: u64 {
///         Foo = 0b001,
///         Bar = 0b010,
///         Baz = 0b100
///     }
///
///     #[repr(u32)]
///     enum Flag128: u128 {
///         Foo = 0b001,
///         Bar = 0b010,
///         Baz = 0b100
///     }
/// }
///
/// assert_eq!(size_of::<Flag8>(), 1);
/// assert_eq!(size_of::<Flag16>(), 1);
/// assert_eq!(size_of::<Flag32>(), 1);
/// assert_eq!(size_of::<Flag64>(), 8);
/// assert_eq!(size_of::<Flag128>(), 4);
///
/// assert_eq!(align_of::<Flag8>(), 1);
/// assert_eq!(align_of::<Flag16>(), 1);
/// assert_eq!(align_of::<Flag32>(), 1);
/// assert_eq!(align_of::<Flag64>(), align_of::<u64>());
/// assert_eq!(align_of::<Flag128>(), align_of::<u32>());
///
/// assert_eq!(size_of::<FlagSet<Flag8>>(), size_of::<u8>());
/// assert_eq!(size_of::<FlagSet<Flag16>>(), size_of::<u16>());
/// assert_eq!(size_of::<FlagSet<Flag32>>(), size_of::<u32>());
/// assert_eq!(size_of::<FlagSet<Flag64>>(), size_of::<u64>());
/// assert_eq!(size_of::<FlagSet<Flag128>>(), size_of::<u128>());
///
/// assert_eq!(align_of::<FlagSet<Flag8>>(), align_of::<u8>());
/// assert_eq!(align_of::<FlagSet<Flag16>>(), align_of::<u16>());
/// assert_eq!(align_of::<FlagSet<Flag32>>(), align_of::<u32>());
/// assert_eq!(align_of::<FlagSet<Flag64>>(), align_of::<u64>());
/// assert_eq!(align_of::<FlagSet<Flag128>>(), align_of::<u128>());
/// ```
#[macro_export]
macro_rules! flags {
    () => {};

    // Entry point for enumerations without values.
    ($(#[$m:meta])* $p:vis enum $n:ident: $t:ty { $($(#[$a:meta])* $k:ident),+ $(,)* } $($next:tt)*) => {
        $crate::flags! { $(#[$m])* $p enum $n: $t { $($(#[$a])* $k = (1 << $n::$k as $t)),+ } $($next)* }
    };

    // Entrypoint for enumerations with values.
    ($(#[$m:meta])* $p:vis enum $n:ident: $t:ty { $($(#[$a:meta])*$k:ident = $v:expr),* $(,)* } $($next:tt)*) => {
        $(#[$m])*
        #[derive(Copy, Clone, Debug, PartialEq, Eq)]
        $p enum $n { $($(#[$a])* $k),* }

        impl $crate::Flags for $n {
            type Type = $t;

            const LIST: &'static [Self] = &[$($n::$k),*];
        }

        impl core::convert::From<$n> for $crate::FlagSet<$n> {
            #[inline]
            fn from(value: $n) -> Self {
                unsafe {
                    match value {
                        $($n::$k => Self::new_unchecked($v)),*
                    }
                }
            }
        }

        impl core::ops::Not for $n {
            type Output = $crate::FlagSet<$n>;

            #[inline]
            fn not(self) -> Self::Output {
                !$crate::FlagSet::from(self)
            }
        }

        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::BitAnd<R> for $n {
            type Output = $crate::FlagSet<$n>;

            #[inline]
            fn bitand(self, rhs: R) -> Self::Output {
                $crate::FlagSet::from(self) & rhs
            }
        }

        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::BitOr<R> for $n {
            type Output = $crate::FlagSet<$n>;

            #[inline]
            fn bitor(self, rhs: R) -> Self::Output {
                $crate::FlagSet::from(self) | rhs
            }
        }

        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::BitXor<R> for $n {
            type Output = $crate::FlagSet<$n>;

            #[inline]
            fn bitxor(self, rhs: R) -> Self::Output {
                $crate::FlagSet::from(self) ^ rhs
            }
        }

        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::Sub<R> for $n {
            type Output = $crate::FlagSet<$n>;

            #[inline]
            fn sub(self, rhs: R) -> Self::Output {
                $crate::FlagSet::from(self) - rhs
            }
        }

        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::Rem<R> for $n {
            type Output = $crate::FlagSet<$n>;

            #[inline]
            fn rem(self, rhs: R) -> Self::Output {
                $crate::FlagSet::from(self) % rhs
            }
        }

        $crate::flags! { $($next)* }
    };
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/leb128-0.2.5/src/lib.rs

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//! Read and write DWARF's "Little Endian Base 128" (LEB128) variable length
//! integer encoding.
//!
//! The implementation is a direct translation of the psuedocode in the DWARF 4
//! standard's appendix C.
//!
//! Read and write signed integers:
//!
//! ```
//! use leb128;
//!
//! let mut buf = [0; 1024];
//!
//! // Write to anything that implements `std::io::Write`.
//! {
//!     let mut writable = &mut buf[..];
//!     leb128::write::signed(&mut writable, -12345).expect("Should write number");
//! }
//!
//! // Read from anything that implements `std::io::Read`.
//! let mut readable = &buf[..];
//! let val = leb128::read::signed(&mut readable).expect("Should read number");
//! assert_eq!(val, -12345);
//! ```
//!
//! Or read and write unsigned integers:
//!
//! ```
//! use leb128;
//!
//! let mut buf = [0; 1024];
//!
//! {
//!     let mut writable = &mut buf[..];
//!     leb128::write::unsigned(&mut writable, 98765).expect("Should write number");
//! }
//!
//! let mut readable = &buf[..];
//! let val = leb128::read::unsigned(&mut readable).expect("Should read number");
//! assert_eq!(val, 98765);
//! ```

#![deny(missing_docs)]

#[doc(hidden)]
pub const CONTINUATION_BIT: u8 = 1 << 7;
#[doc(hidden)]
pub const SIGN_BIT: u8 = 1 << 6;

#[doc(hidden)]
#[inline]
pub fn low_bits_of_byte(byte: u8) -> u8 {
    byte & !CONTINUATION_BIT
}

#[doc(hidden)]
#[inline]
pub fn low_bits_of_u64(val: u64) -> u8 {
    let byte = val & (std::u8::MAX as u64);
    low_bits_of_byte(byte as u8)
}

/// A module for reading LEB128-encoded signed and unsigned integers.
pub mod read {
    use super::{low_bits_of_byte, CONTINUATION_BIT, SIGN_BIT};
    use std::fmt;
    use std::io;

    /// An error type for reading LEB128-encoded values.
    #[derive(Debug)]
    pub enum Error {
        /// There was an underlying IO error.
        IoError(io::Error),
        /// The number being read is larger than can be represented.
        Overflow,
    }

    impl From<io::Error> for Error {
        fn from(e: io::Error) -> Self {
            Error::IoError(e)
        }
    }

    impl fmt::Display for Error {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
            match *self {
                Error::IoError(ref e) => e.fmt(f),
                Error::Overflow => {
                    write!(f, "The number being read is larger than can be represented")
                }
            }
        }
    }

    impl std::error::Error for Error {
        fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
            match *self {
                Error::IoError(ref e) => Some(e),
                Error::Overflow => None,
            }
        }
    }

    /// Read an unsigned LEB128-encoded number from the `std::io::Read` stream
    /// `r`.
    ///
    /// On success, return the number.
    pub fn unsigned<R>(r: &mut R) -> Result<u64, Error>
    where
        R: ?Sized + io::Read,
    {
        let mut result = 0;
        let mut shift = 0;

        loop {
            let mut buf = [0];
            r.read_exact(&mut buf)?;

            if shift == 63 && buf[0] != 0x00 && buf[0] != 0x01 {
                while buf[0] & CONTINUATION_BIT != 0 {
                    r.read_exact(&mut buf)?;
                }
                return Err(Error::Overflow);
            }

            let low_bits = low_bits_of_byte(buf[0]) as u64;
            result |= low_bits << shift;

            if buf[0] & CONTINUATION_BIT == 0 {
                return Ok(result);
            }

            shift += 7;
        }
    }

    /// Read a signed LEB128-encoded number from the `std::io::Read` stream `r`.
    ///
    /// On success, return the number.
    pub fn signed<R>(r: &mut R) -> Result<i64, Error>
    where
        R: ?Sized + io::Read,
    {
        let mut result = 0;
        let mut shift = 0;
        let size = 64;
        let mut byte;

        loop {
            let mut buf = [0];
            r.read_exact(&mut buf)?;

            byte = buf[0];
            if shift == 63 && byte != 0x00 && byte != 0x7f {
                while buf[0] & CONTINUATION_BIT != 0 {
                    r.read_exact(&mut buf)?;
                }
                return Err(Error::Overflow);
            }

            let low_bits = low_bits_of_byte(byte) as i64;
            result |= low_bits << shift;
            shift += 7;

            if byte & CONTINUATION_BIT == 0 {
                break;
            }
        }

        if shift < size && (SIGN_BIT & byte) == SIGN_BIT {
            // Sign extend the result.
            result |= !0 << shift;
        }

        Ok(result)
    }
}

/// A module for writing LEB128-encoded signed and unsigned integers.
pub mod write {
    use super::{low_bits_of_u64, CONTINUATION_BIT};
    use std::io;

    /// Write `val` to the `std::io::Write` stream `w` as an unsigned LEB128 value.
    ///
    /// On success, return the number of bytes written to `w`.
    pub fn unsigned<W>(w: &mut W, mut val: u64) -> Result<usize, io::Error>
    where
        W: ?Sized + io::Write,
    {
        let mut bytes_written = 0;
        loop {
            let mut byte = low_bits_of_u64(val);
            val >>= 7;
            if val != 0 {
                // More bytes to come, so set the continuation bit.
                byte |= CONTINUATION_BIT;
            }

            let buf = [byte];
            w.write_all(&buf)?;
            bytes_written += 1;

            if val == 0 {
                return Ok(bytes_written);
            }
        }
    }

    /// Write `val` to the `std::io::Write` stream `w` as a signed LEB128 value.
    ///
    /// On success, return the number of bytes written to `w`.
    pub fn signed<W>(w: &mut W, mut val: i64) -> Result<usize, io::Error>
    where
        W: ?Sized + io::Write,
    {
        let mut bytes_written = 0;
        loop {
            let mut byte = val as u8;
            // Keep the sign bit for testing
            val >>= 6;
            let done = val == 0 || val == -1;
            if done {
                byte &= !CONTINUATION_BIT;
            } else {
                // Remove the sign bit
                val >>= 1;
                // More bytes to come, so set the continuation bit.
                byte |= CONTINUATION_BIT;
            }

            let buf = [byte];
            w.write_all(&buf)?;
            bytes_written += 1;

            if done {
                return Ok(bytes_written);
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std;
    use std::io;

    #[test]
    fn test_low_bits_of_byte() {
        for i in 0..127 {
            assert_eq!(i, low_bits_of_byte(i));
            assert_eq!(i, low_bits_of_byte(i | CONTINUATION_BIT));
        }
    }

    #[test]
    fn test_low_bits_of_u64() {
        for i in 0u64..127 {
            assert_eq!(i as u8, low_bits_of_u64(1 << 16 | i));
            assert_eq!(
                i as u8,
                low_bits_of_u64(i << 16 | i | (CONTINUATION_BIT as u64))
            );
        }
    }

    // Examples from the DWARF 4 standard, section 7.6, figure 22.
    #[test]
    fn test_read_unsigned() {
        let buf = [2u8];
        let mut readable = &buf[..];
        assert_eq!(
            2,
            read::unsigned(&mut readable).expect("Should read number")
        );

        let buf = [127u8];
        let mut readable = &buf[..];
        assert_eq!(
            127,
            read::unsigned(&mut readable).expect("Should read number")
        );

        let buf = [CONTINUATION_BIT, 1];
        let mut readable = &buf[..];
        assert_eq!(
            128,
            read::unsigned(&mut readable).expect("Should read number")
        );

        let buf = [1u8 | CONTINUATION_BIT, 1];
        let mut readable = &buf[..];
        assert_eq!(
            129,
            read::unsigned(&mut readable).expect("Should read number")
        );

        let buf = [2u8 | CONTINUATION_BIT, 1];
        let mut readable = &buf[..];
        assert_eq!(
            130,
            read::unsigned(&mut readable).expect("Should read number")
        );

        let buf = [57u8 | CONTINUATION_BIT, 100];
        let mut readable = &buf[..];
        assert_eq!(
            12857,
            read::unsigned(&mut readable).expect("Should read number")
        );
    }

    #[test]
    fn test_read_unsigned_thru_dyn_trait() {
        fn read(r: &mut dyn io::Read) -> u64 {
            read::unsigned(r).expect("Should read number")
        }

        let buf = [0u8];

        let mut readable = &buf[..];
        assert_eq!(0, read(&mut readable));

        let mut readable = io::Cursor::new(buf);
        assert_eq!(0, read(&mut readable));
    }

    // Examples from the DWARF 4 standard, section 7.6, figure 23.
    #[test]
    fn test_read_signed() {
        let buf = [2u8];
        let mut readable = &buf[..];
        assert_eq!(2, read::signed(&mut readable).expect("Should read number"));

        let buf = [0x7eu8];
        let mut readable = &buf[..];
        assert_eq!(-2, read::signed(&mut readable).expect("Should read number"));

        let buf = [127u8 | CONTINUATION_BIT, 0];
        let mut readable = &buf[..];
        assert_eq!(
            127,
            read::signed(&mut readable).expect("Should read number")
        );

        let buf = [1u8 | CONTINUATION_BIT, 0x7f];
        let mut readable = &buf[..];
        assert_eq!(
            -127,
            read::signed(&mut readable).expect("Should read number")
        );

        let buf = [CONTINUATION_BIT, 1];
        let mut readable = &buf[..];
        assert_eq!(
            128,
            read::signed(&mut readable).expect("Should read number")
        );

        let buf = [CONTINUATION_BIT, 0x7f];
        let mut readable = &buf[..];
        assert_eq!(
            -128,
            read::signed(&mut readable).expect("Should read number")
        );

        let buf = [1u8 | CONTINUATION_BIT, 1];
        let mut readable = &buf[..];
        assert_eq!(
            129,
            read::signed(&mut readable).expect("Should read number")
        );

        let buf = [0x7fu8 | CONTINUATION_BIT, 0x7e];
        let mut readable = &buf[..];
        assert_eq!(
            -129,
            read::signed(&mut readable).expect("Should read number")
        );
    }

    #[test]
    fn test_read_signed_thru_dyn_trait() {
        fn read(r: &mut dyn io::Read) -> i64 {
            read::signed(r).expect("Should read number")
        }

        let buf = [0u8];

        let mut readable = &buf[..];
        assert_eq!(0, read(&mut readable));

        let mut readable = io::Cursor::new(buf);
        assert_eq!(0, read(&mut readable));
    }

    #[test]
    fn test_read_signed_63_bits() {
        let buf = [
            CONTINUATION_BIT,
            CONTINUATION_BIT,
            CONTINUATION_BIT,
            CONTINUATION_BIT,
            CONTINUATION_BIT,
            CONTINUATION_BIT,
            CONTINUATION_BIT,
            CONTINUATION_BIT,
            0x40,
        ];
        let mut readable = &buf[..];
        assert_eq!(
            -0x4000000000000000,
            read::signed(&mut readable).expect("Should read number")
        );
    }

    #[test]
    fn test_read_unsigned_not_enough_data() {
        let buf = [CONTINUATION_BIT];
        let mut readable = &buf[..];
        match read::unsigned(&mut readable) {
            Err(read::Error::IoError(e)) => assert_eq!(e.kind(), io::ErrorKind::UnexpectedEof),
            otherwise => panic!("Unexpected: {:?}", otherwise),
        }
    }

    #[test]
    fn test_read_signed_not_enough_data() {
        let buf = [CONTINUATION_BIT];
        let mut readable = &buf[..];
        match read::signed(&mut readable) {
            Err(read::Error::IoError(e)) => assert_eq!(e.kind(), io::ErrorKind::UnexpectedEof),
            otherwise => panic!("Unexpected: {:?}", otherwise),
        }
    }

    #[test]
    fn test_write_unsigned_not_enough_space() {
        let mut buf = [0; 1];
        let mut writable = &mut buf[..];
        match write::unsigned(&mut writable, 128) {
            Err(e) => assert_eq!(e.kind(), io::ErrorKind::WriteZero),
            otherwise => panic!("Unexpected: {:?}", otherwise),
        }
    }

    #[test]
    fn test_write_signed_not_enough_space() {
        let mut buf = [0; 1];
        let mut writable = &mut buf[..];
        match write::signed(&mut writable, 128) {
            Err(e) => assert_eq!(e.kind(), io::ErrorKind::WriteZero),
            otherwise => panic!("Unexpected: {:?}", otherwise),
        }
    }

    #[test]
    fn test_write_unsigned_thru_dyn_trait() {
        fn write(w: &mut dyn io::Write, val: u64) -> usize {
            write::unsigned(w, val).expect("Should write number")
        }
        let mut buf = [0u8; 1];

        let mut writable = &mut buf[..];
        assert_eq!(write(&mut writable, 0), 1);
        assert_eq!(buf[0], 0);

        let mut writable = Vec::from(&buf[..]);
        assert_eq!(write(&mut writable, 0), 1);
        assert_eq!(buf[0], 0);
    }

    #[test]
    fn test_write_signed_thru_dyn_trait() {
        fn write(w: &mut dyn io::Write, val: i64) -> usize {
            write::signed(w, val).expect("Should write number")
        }
        let mut buf = [0u8; 1];

        let mut writable = &mut buf[..];
        assert_eq!(write(&mut writable, 0), 1);
        assert_eq!(buf[0], 0);

        let mut writable = Vec::from(&buf[..]);
        assert_eq!(write(&mut writable, 0), 1);
        assert_eq!(buf[0], 0);
    }

    #[test]
    fn dogfood_signed() {
        fn inner(i: i64) {
            let mut buf = [0u8; 1024];

            {
                let mut writable = &mut buf[..];
                write::signed(&mut writable, i).expect("Should write signed number");
            }

            let mut readable = &buf[..];
            let result = read::signed(&mut readable).expect("Should be able to read it back again");
            assert_eq!(i, result);
        }
        for i in -513..513 {
            inner(i);
        }
        inner(std::i64::MIN);
    }

    #[test]
    fn dogfood_unsigned() {
        for i in 0..1025 {
            let mut buf = [0u8; 1024];

            {
                let mut writable = &mut buf[..];
                write::unsigned(&mut writable, i).expect("Should write signed number");
            }

            let mut readable = &buf[..];
            let result =
                read::unsigned(&mut readable).expect("Should be able to read it back again");
            assert_eq!(i, result);
        }
    }

    #[test]
    fn test_read_unsigned_overflow() {
        let buf = [
            2u8 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            1,
        ];
        let mut readable = &buf[..];
        assert!(read::unsigned(&mut readable).is_err());
    }

    #[test]
    fn test_read_signed_overflow() {
        let buf = [
            2u8 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            2 | CONTINUATION_BIT,
            1,
        ];
        let mut readable = &buf[..];
        assert!(read::signed(&mut readable).is_err());
    }

    #[test]
    fn test_read_multiple() {
        let buf = [2u8 | CONTINUATION_BIT, 1u8, 1u8];

        let mut readable = &buf[..];
        assert_eq!(
            read::unsigned(&mut readable).expect("Should read first number"),
            130u64
        );
        assert_eq!(
            read::unsigned(&mut readable).expect("Should read first number"),
            1u64
        );
    }

    #[test]
    fn test_read_multiple_with_overflow() {
        let buf = [
            0b1111_1111,
            0b1111_1111,
            0b1111_1111,
            0b1111_1111,
            0b1111_1111,
            0b1111_1111,
            0b1111_1111,
            0b1111_1111,
            0b1111_1111,
            0b1111_1111,
            0b0111_1111, // Overflow!
            0b1110_0100,
            0b1110_0000,
            0b0000_0010, // 45156
        ];
        let mut readable = &buf[..];

        assert!(if let read::Error::Overflow =
            read::unsigned(&mut readable).expect_err("Should fail with Error::Overflow")
        {
            true
        } else {
            false
        });
        assert_eq!(
            read::unsigned(&mut readable).expect("Should succeed with correct value"),
            45156
        );
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/libfuzzer-sys-0.4.7/src/lib.rs

Source (jump to first uncovered line)
//! Bindings to [libFuzzer](http://llvm.org/docs/LibFuzzer.html): a runtime for
//! coverage-guided fuzzing.
//!
//! See [the `cargo-fuzz`
//! guide](https://rust-fuzz.github.io/book/cargo-fuzz.html) for a usage
//! tutorial.
//!
//! The main export of this crate is [the `fuzz_target!`
//! macro](./macro.fuzz_target.html), which allows you to define targets for
//! libFuzzer to exercise.

#![deny(missing_docs, missing_debug_implementations)]

pub use arbitrary;
use once_cell::sync::OnceCell;

/// Indicates whether the input should be kept in the corpus or rejected. This
/// should be returned by your fuzz target. If your fuzz target does not return
/// a value (i.e., returns `()`), then the input will be kept in the corpus.
#[derive(Debug)]
pub enum Corpus {
    /// Keep the input in the corpus.
    Keep,

    /// Reject the input and do not keep it in the corpus.
    Reject,
}

impl From<()> for Corpus {
    fn from(_: ()) -> Self {
        Self::Keep
    }
}

impl Corpus {
    #[doc(hidden)]
    /// Convert this Corpus result into the [integer codes used by
    /// `libFuzzer`](https://llvm.org/docs/LibFuzzer.html#rejecting-unwanted-inputs).
    /// This is -1 for reject, 0 for keep.
    pub fn to_libfuzzer_code(self) -> i32 {
        match self {
            Corpus::Keep => 0,
            Corpus::Reject => -1,
        }
    }
}

extern "C" {
    // We do not actually cross the FFI bound here.
    #[allow(improper_ctypes)]
    fn rust_fuzzer_test_input(input: &[u8]) -> i32;

    fn LLVMFuzzerMutate(data: *mut u8, size: usize, max_size: usize) -> usize;
}

#[doc(hidden)]
#[export_name = "LLVMFuzzerTestOneInput"]
pub fn test_input_wrap(data: *const u8, size: usize) -> i32 {
    let test_input = ::std::panic::catch_unwind(|| unsafe {
        let data_slice = ::std::slice::from_raw_parts(data, size);
        rust_fuzzer_test_input(data_slice)
    });

    match test_input {
        Ok(i) => i,
        Err(_) => {
            // hopefully the custom panic hook will be called before and abort the
            // process before the stack frames are unwinded.
            ::std::process::abort();
        }
    }
}

#[doc(hidden)]
pub static RUST_LIBFUZZER_DEBUG_PATH: OnceCell<String> = OnceCell::new();

#[doc(hidden)]
#[export_name = "LLVMFuzzerInitialize"]
pub fn initialize(_argc: *const isize, _argv: *const *const *const u8) -> isize {
    // Registers a panic hook that aborts the process before unwinding.
    // It is useful to abort before unwinding so that the fuzzer will then be
    // able to analyse the process stack frames to tell different bugs appart.
    //
    // HACK / FIXME: it would be better to use `-C panic=abort` but it's currently
    // impossible to build code using compiler plugins with this flag.
    // We will be able to remove this code when
    // https://github.com/rust-lang/cargo/issues/5423 is fixed.
    let default_hook = ::std::panic::take_hook();
    ::std::panic::set_hook(Box::new(move |panic_info| {
        default_hook(panic_info);
        ::std::process::abort();
    }));

    // Initialize the `RUST_LIBFUZZER_DEBUG_PATH` cell with the path so it can be
    // reused with little overhead.
    if let Ok(path) = std::env::var("RUST_LIBFUZZER_DEBUG_PATH") {
        RUST_LIBFUZZER_DEBUG_PATH
            .set(path)
            .expect("Since this is initialize it is only called once so can never fail");
    }
    0
}

/// Define a fuzz target.
///
/// ## Example
///
/// This example takes a `&[u8]` slice and attempts to parse it. The parsing
/// might fail and return an `Err`, but it shouldn't ever panic or segfault.
///
/// ```no_run
/// #![no_main]
///
/// use libfuzzer_sys::fuzz_target;
///
/// // Note: `|input|` is short for `|input: &[u8]|`.
/// fuzz_target!(|input| {
///     let _result: Result<_, _> = my_crate::parse(input);
/// });
/// # mod my_crate { pub fn parse(_: &[u8]) -> Result<(), ()> { unimplemented!() } }
/// ```
///
/// ## Rejecting Inputs
///
/// It may be desirable to reject some inputs, i.e. to not add them to the
/// corpus.
///
/// For example, when fuzzing an API consisting of parsing and other logic,
/// one may want to allow only those inputs into the corpus that parse
/// successfully. To indicate whether an input should be kept in or rejected
/// from the corpus, return either [Corpus::Keep] or [Corpus::Reject] from your
/// fuzz target. The default behavior (e.g. if `()` is returned) is to keep the
/// input in the corpus.
///
/// For example:
///
/// ```no_run
/// #![no_main]
///
/// use libfuzzer_sys::{Corpus, fuzz_target};
///
/// fuzz_target!(|input: String| -> Corpus {
///     let parts: Vec<&str> = input.splitn(2, '=').collect();
///     if parts.len() != 2 {
///         return Corpus::Reject;
///     }
///
///     let key = parts[0];
///     let value = parts[1];
///     let _result: Result<_, _> = my_crate::parse(key, value);
///     Corpus::Keep
/// });
/// # mod my_crate { pub fn parse(_key: &str, _value: &str) -> Result<(), ()> { unimplemented!() } }
/// ```
///
/// ## Arbitrary Input Types
///
/// The input is a `&[u8]` slice by default, but you can take arbitrary input
/// types, as long as the type implements [the `arbitrary` crate's `Arbitrary`
/// trait](https://docs.rs/arbitrary/*/arbitrary/trait.Arbitrary.html) (which is
/// also re-exported as `libfuzzer_sys::arbitrary::Arbitrary` for convenience).
///
/// For example, if you wanted to take an arbitrary RGB color, you could do the
/// following:
///
/// ```no_run
/// #![no_main]
/// # mod foo {
///
/// use libfuzzer_sys::{arbitrary::{Arbitrary, Error, Unstructured}, fuzz_target};
///
/// #[derive(Debug)]
/// pub struct Rgb {
///     r: u8,
///     g: u8,
///     b: u8,
/// }
///
/// impl<'a> Arbitrary<'a> for Rgb {
///     fn arbitrary(raw: &mut Unstructured<'a>) -> Result<Self, Error> {
///         let mut buf = [0; 3];
///         raw.fill_buffer(&mut buf)?;
///         let r = buf[0];
///         let g = buf[1];
///         let b = buf[2];
///         Ok(Rgb { r, g, b })
///     }
/// }
///
/// // Write a fuzz target that works with RGB colors instead of raw bytes.
/// fuzz_target!(|color: Rgb| {
///     my_crate::convert_color(color);
/// });
/// # mod my_crate {
/// #     use super::Rgb;
/// #     pub fn convert_color(_: Rgb) {}
/// # }
/// # }
/// ```
///
/// You can also enable the `arbitrary` crate's custom derive via this crate's
/// `"arbitrary-derive"` cargo feature.
#[macro_export]
macro_rules! fuzz_target {
    (|$bytes:ident| $body:expr) => {
        const _: () = {
            /// Auto-generated function
            #[no_mangle]
            pub extern "C" fn rust_fuzzer_test_input(bytes: &[u8]) -> i32 {
                // When `RUST_LIBFUZZER_DEBUG_PATH` is set, write the debug
                // formatting of the input to that file. This is only intended for
                // `cargo fuzz`'s use!

                // `RUST_LIBFUZZER_DEBUG_PATH` is set in initialization.
                if let Some(path) = $crate::RUST_LIBFUZZER_DEBUG_PATH.get() {
                    use std::io::Write;
                    let mut file = std::fs::File::create(path)
                        .expect("failed to create `RUST_LIBFUZZER_DEBUG_PATH` file");
                    writeln!(&mut file, "{:?}", bytes)
                        .expect("failed to write to `RUST_LIBFUZZER_DEBUG_PATH` file");
                    return 0;
                }

                __libfuzzer_sys_run(bytes);
                0
            }

            // Split out the actual fuzzer into a separate function which is
            // tagged as never being inlined. This ensures that if the fuzzer
            // panics there's at least one stack frame which is named uniquely
            // according to this specific fuzzer that this is embedded within.
            //
            // Systems like oss-fuzz try to deduplicate crashes and without this
            // panics in separate fuzzers can accidentally appear the same
            // because each fuzzer will have a function called
            // `rust_fuzzer_test_input`. By using a normal Rust function here
            // it's named something like `the_fuzzer_name::_::__libfuzzer_sys_run` which should
            // ideally help prevent oss-fuzz from deduplicate fuzz bugs across
            // distinct targets accidentally.
            #[inline(never)]
            fn __libfuzzer_sys_run($bytes: &[u8]) {
                $body
            }
        };
    };

    (|$data:ident: &[u8]| $body:expr) => {
        $crate::fuzz_target!(|$data| $body);
    };

    (|$data:ident: $dty:ty| $body:expr) => {
        $crate::fuzz_target!(|$data: $dty| -> () { $body });
    };

    (|$data:ident: $dty:ty| -> $rty:ty $body:block) => {
        const _: () = {
            /// Auto-generated function
            #[no_mangle]
            pub extern "C" fn rust_fuzzer_test_input(bytes: &[u8]) -> i32 {
                use $crate::arbitrary::{Arbitrary, Unstructured};

                // Early exit if we don't have enough bytes for the `Arbitrary`
                // implementation. This helps the fuzzer avoid exploring all the
                // different not-enough-input-bytes paths inside the `Arbitrary`
                // implementation. Additionally, it exits faster, letting the fuzzer
                // get to longer inputs that actually lead to interesting executions
                // quicker.
                if bytes.len() < <$dty as Arbitrary>::size_hint(0).0 {
                    return -1;
                }

                let mut u = Unstructured::new(bytes);
                let data = <$dty as Arbitrary>::arbitrary_take_rest(u);

                // When `RUST_LIBFUZZER_DEBUG_PATH` is set, write the debug
                // formatting of the input to that file. This is only intended for
                // `cargo fuzz`'s use!

                // `RUST_LIBFUZZER_DEBUG_PATH` is set in initialization.
                if let Some(path) = $crate::RUST_LIBFUZZER_DEBUG_PATH.get() {
                    use std::io::Write;
                    let mut file = std::fs::File::create(path)
                        .expect("failed to create `RUST_LIBFUZZER_DEBUG_PATH` file");
                    (match data {
                        Ok(data) => writeln!(&mut file, "{:#?}", data),
                        Err(err) => writeln!(&mut file, "Arbitrary Error: {}", err),
                    })
                    .expect("failed to write to `RUST_LIBFUZZER_DEBUG_PATH` file");
                    return -1;
                }

                let data = match data {
                    Ok(d) => d,
                    Err(_) => return -1,
                };

                let result = ::libfuzzer_sys::Corpus::from(__libfuzzer_sys_run(data));
                result.to_libfuzzer_code()
            }

            // See above for why this is split to a separate function.
            #[inline(never)]
            fn __libfuzzer_sys_run($data: $dty) -> $rty {
                $body
            }
        };
    };
}

/// Define a custom mutator.
///
/// This is optional, and libFuzzer will use its own, default mutation strategy
/// if this is not provided.
///
/// You might consider using a custom mutator when your fuzz target is very
/// particular about the shape of its input:
///
/// * You want to fuzz "deeper" than just the parser.
/// * The input contains checksums that have to match the hash of some subset of
///   the data or else the whole thing is invalid, and therefore mutating any of
///   that subset means you need to recompute the checksums.
/// * Small random changes to the input buffer make it invalid.
///
/// That is, a custom mutator is useful in similar situations where [a `T:
/// Arbitrary` input type](macro.fuzz_target.html#arbitrary-input-types) is
/// useful. Note that the two approaches are not mutually exclusive; you can use
/// whichever is easier for your problem domain or both!
///
/// ## Implementation Contract
///
/// The original, unmodified input is given in `data[..size]`.
///
/// You must modify the data in place and return the new size.
///
/// The new size should not be greater than `max_size`. If this is not the case,
/// then the `data` will be truncated to fit within `max_size`. Note that
/// `max_size < size` is possible when shrinking test cases.
///
/// You must produce the same mutation given the same `seed`. Generally, when
/// choosing what kind of mutation to make or where to mutate, you should start
/// by creating a random number generator (RNG) that is seeded with the given
/// `seed` and then consult the RNG whenever making a decision:
///
/// ```no_run
/// #![no_main]
///
/// use rand::{rngs::StdRng, Rng, SeedableRng};
///
/// libfuzzer_sys::fuzz_mutator!(|data: &mut [u8], size: usize, max_size: usize, seed: u32| {
///     let mut rng = StdRng::seed_from_u64(seed as u64);
///
/// #   let first_mutation = |_, _, _, _| todo!();
/// #   let second_mutation = |_, _, _, _| todo!();
/// #   let third_mutation = |_, _, _, _| todo!();
/// #   let fourth_mutation = |_, _, _, _| todo!();
///     // Choose which of our four supported kinds of mutations we want to make.
///     match rng.gen_range(0..4) {
///         0 => first_mutation(rng, data, size, max_size),
///         1 => second_mutation(rng, data, size, max_size),
///         2 => third_mutation(rng, data, size, max_size),
///         3 => fourth_mutation(rng, data, size, max_size),
///         _ => unreachable!()
///     }
/// });
/// ```
///
/// ## Example: Compression
///
/// Consider a simple fuzz target that takes compressed data as input,
/// decompresses it, and then asserts that the decompressed data doesn't begin
/// with "boom". It is difficult for `libFuzzer` (or any other fuzzer) to crash
/// this fuzz target because nearly all mutations it makes will invalidate the
/// compression format. Therefore, we use a custom mutator that decompresses the
/// raw input, mutates the decompressed data, and then recompresses it. This
/// allows `libFuzzer` to quickly discover crashing inputs.
///
/// ```no_run
/// #![no_main]
///
/// use flate2::{read::GzDecoder, write::GzEncoder, Compression};
/// use libfuzzer_sys::{fuzz_mutator, fuzz_target};
/// use std::io::{Read, Write};
///
/// fuzz_target!(|data: &[u8]| {
///     // Decompress the input data and crash if it starts with "boom".
///     if let Some(data) = decompress(data) {
///         if data.starts_with(b"boom") {
///             panic!();
///         }
///     }
/// });
///
/// fuzz_mutator!(
///     |data: &mut [u8], size: usize, max_size: usize, _seed: u32| {
///         // Decompress the input data. If that fails, use a dummy value.
///         let mut decompressed = decompress(&data[..size]).unwrap_or_else(|| b"hi".to_vec());
///
///         // Mutate the decompressed data with `libFuzzer`'s default mutator. Make
///         // the `decompressed` vec's extra capacity available for insertion
///         // mutations via `resize`.
///         let len = decompressed.len();
///         let cap = decompressed.capacity();
///         decompressed.resize(cap, 0);
///         let new_decompressed_size = libfuzzer_sys::fuzzer_mutate(&mut decompressed, len, cap);
///
///         // Recompress the mutated data.
///         let compressed = compress(&decompressed[..new_decompressed_size]);
///
///         // Copy the recompressed mutated data into `data` and return the new size.
///         let new_size = std::cmp::min(max_size, compressed.len());
///         data[..new_size].copy_from_slice(&compressed[..new_size]);
///         new_size
///     }
/// );
///
/// fn decompress(compressed_data: &[u8]) -> Option<Vec<u8>> {
///     let mut decoder = GzDecoder::new(compressed_data);
///     let mut decompressed = Vec::new();
///     if decoder.read_to_end(&mut decompressed).is_ok() {
///         Some(decompressed)
///     } else {
///         None
///     }
/// }
///
/// fn compress(data: &[u8]) -> Vec<u8> {
///     let mut encoder = GzEncoder::new(Vec::new(), Compression::default());
///     encoder
///         .write_all(data)
///         .expect("writing into a vec is infallible");
///     encoder.finish().expect("writing into a vec is infallible")
/// }
/// ```
///
/// This example is inspired by [a similar example from the official `libFuzzer`
/// docs](https://github.com/google/fuzzing/blob/master/docs/structure-aware-fuzzing.md#example-compression).
///
/// ## More Example Ideas
///
/// * A PNG custom mutator that decodes a PNG, mutates the image, and then
/// re-encodes the mutated image as a new PNG.
///
/// * A [`serde`](https://serde.rs/) custom mutator that deserializes your
///   structure, mutates it, and then reserializes it.
///
/// * A Wasm binary custom mutator that inserts, replaces, and removes a
///   bytecode instruction in a function's body.
///
/// * An HTTP request custom mutator that inserts, replaces, and removes a
///   header from an HTTP request.
#[macro_export]
macro_rules! fuzz_mutator {
    (
        |
        $data:ident : &mut [u8] ,
        $size:ident : usize ,
        $max_size:ident : usize ,
        $seed:ident : u32 $(,)*
        |
        $body:block
    ) => {
        /// Auto-generated function.
        #[export_name = "LLVMFuzzerCustomMutator"]
        pub fn rust_fuzzer_custom_mutator(
            $data: *mut u8,
            $size: usize,
            $max_size: usize,
            $seed: std::os::raw::c_uint,
        ) -> usize {
            // Depending on if we are growing or shrinking the test case, `size`
            // might be larger or smaller than `max_size`. The `data`'s capacity
            // is the maximum of the two.
            let len = std::cmp::max($max_size, $size);
            let $data: &mut [u8] = unsafe { std::slice::from_raw_parts_mut($data, len) };

            // `unsigned int` is generally a `u32`, but not on all targets. Do
            // an infallible (and potentially lossy, but that's okay because it
            // preserves determinism) conversion.
            let $seed = $seed as u32;

            // Truncate the new size if it is larger than the max.
            let new_size = { $body };
            std::cmp::min(new_size, $max_size)
        }
    };
}

/// The default `libFuzzer` mutator.
///
/// You generally don't have to use this at all unless you're defining a
/// custom mutator with [the `fuzz_mutator!` macro][crate::fuzz_mutator].
///
/// Mutates `data[..size]` in place such that the mutated data is no larger than
/// `max_size` and returns the new size of the mutated data.
///
/// To only allow shrinking mutations, make `max_size < size`.
///
/// To additionally allow mutations that grow the size of the data, make
/// `max_size > size`.
///
/// Both `size` and `max_size` must be less than or equal to `data.len()`.
///
/// # Example
///
/// ```no_run
/// // Create some data in a buffer.
/// let mut data = vec![0; 128];
/// data[..b"hello".len()].copy_from_slice(b"hello");
///
/// // Ask `libFuzzer` to mutate the data. By setting `max_size` to our buffer's
/// // full length, we are allowing `libFuzzer` to perform mutations that grow
/// // the size of the data, such as insertions.
/// let size = b"hello".len();
/// let max_size = data.len();
/// let new_size = libfuzzer_sys::fuzzer_mutate(&mut data, size, max_size);
///
/// // Get the mutated data out of the buffer.
/// let mutated_data = &data[..new_size];
/// ```
pub fn fuzzer_mutate(data: &mut [u8], size: usize, max_size: usize) -> usize {
    assert!(size <= data.len());
    assert!(max_size <= data.len());
    let new_size = unsafe { LLVMFuzzerMutate(data.as_mut_ptr(), size, max_size) };
    assert!(new_size <= data.len());
    new_size
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/once_cell-1.19.0/src/imp_std.rs

Source (jump to first uncovered line)
// There's a lot of scary concurrent code in this module, but it is copied from
// `std::sync::Once` with two changes:
//   * no poisoning
//   * init function can fail

use std::{
    cell::{Cell, UnsafeCell},
    panic::{RefUnwindSafe, UnwindSafe},
    sync::atomic::{AtomicBool, AtomicPtr, Ordering},
    thread::{self, Thread},
};

#[derive(Debug)]
pub(crate) struct OnceCell<T> {
    // This `queue` field is the core of the implementation. It encodes two
    // pieces of information:
    //
    // * The current state of the cell (`INCOMPLETE`, `RUNNING`, `COMPLETE`)
    // * Linked list of threads waiting for the current cell.
    //
    // State is encoded in two low bits. Only `INCOMPLETE` and `RUNNING` states
    // allow waiters.
    queue: AtomicPtr<Waiter>,
    value: UnsafeCell<Option<T>>,
}

// Why do we need `T: Send`?
// Thread A creates a `OnceCell` and shares it with
// scoped thread B, which fills the cell, which is
// then destroyed by A. That is, destructor observes
// a sent value.
unsafe impl<T: Sync + Send> Sync for OnceCell<T> {}
unsafe impl<T: Send> Send for OnceCell<T> {}

impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceCell<T> {}
impl<T: UnwindSafe> UnwindSafe for OnceCell<T> {}

impl<T> OnceCell<T> {
    pub(crate) const fn new() -> OnceCell<T> {
        OnceCell { queue: AtomicPtr::new(INCOMPLETE_PTR), value: UnsafeCell::new(None) }
    }

    pub(crate) const fn with_value(value: T) -> OnceCell<T> {
        OnceCell { queue: AtomicPtr::new(COMPLETE_PTR), value: UnsafeCell::new(Some(value)) }
    }

    /// Safety: synchronizes with store to value via Release/(Acquire|SeqCst).
    #[inline]
    pub(crate) fn is_initialized(&self) -> bool {
        // An `Acquire` load is enough because that makes all the initialization
        // operations visible to us, and, this being a fast path, weaker
        // ordering helps with performance. This `Acquire` synchronizes with
        // `SeqCst` operations on the slow path.
        self.queue.load(Ordering::Acquire) == COMPLETE_PTR
    }

    /// Safety: synchronizes with store to value via SeqCst read from state,
    /// writes value only once because we never get to INCOMPLETE state after a
    /// successful write.
    #[cold]
    pub(crate) fn initialize<F, E>(&self, f: F) -> Result<(), E>
    where
        F: FnOnce() -> Result<T, E>,
    {
        let mut f = Some(f);
        let mut res: Result<(), E> = Ok(());
        let slot: *mut Option<T> = self.value.get();
        initialize_or_wait(
            &self.queue,
            Some(&mut || {
                let f = unsafe { f.take().unwrap_unchecked() };
                match f() {
                    Ok(value) => {
                        unsafe { *slot = Some(value) };
                        true
                    }
                    Err(err) => {
                        res = Err(err);
                        false
                    }
                }
            }),
        );
        res
    }

    #[cold]
    pub(crate) fn wait(&self) {
        initialize_or_wait(&self.queue, None);
    }

    /// Get the reference to the underlying value, without checking if the cell
    /// is initialized.
    ///
    /// # Safety
    ///
    /// Caller must ensure that the cell is in initialized state, and that
    /// the contents are acquired by (synchronized to) this thread.
    pub(crate) unsafe fn get_unchecked(&self) -> &T {
        debug_assert!(self.is_initialized());
        let slot = &*self.value.get();
        slot.as_ref().unwrap_unchecked()
    }

    /// Gets the mutable reference to the underlying value.
    /// Returns `None` if the cell is empty.
    pub(crate) fn get_mut(&mut self) -> Option<&mut T> {
        // Safe b/c we have a unique access.
        unsafe { &mut *self.value.get() }.as_mut()
    }

    /// Consumes this `OnceCell`, returning the wrapped value.
    /// Returns `None` if the cell was empty.
    #[inline]
    pub(crate) fn into_inner(self) -> Option<T> {
        // Because `into_inner` takes `self` by value, the compiler statically
        // verifies that it is not currently borrowed.
        // So, it is safe to move out `Option<T>`.
        self.value.into_inner()
    }
}

// Three states that a OnceCell can be in, encoded into the lower bits of `queue` in
// the OnceCell structure.
const INCOMPLETE: usize = 0x0;
const RUNNING: usize = 0x1;
const COMPLETE: usize = 0x2;
const INCOMPLETE_PTR: *mut Waiter = INCOMPLETE as *mut Waiter;
const COMPLETE_PTR: *mut Waiter = COMPLETE as *mut Waiter;

// Mask to learn about the state. All other bits are the queue of waiters if
// this is in the RUNNING state.
const STATE_MASK: usize = 0x3;

/// Representation of a node in the linked list of waiters in the RUNNING state.
/// A waiters is stored on the stack of the waiting threads.
#[repr(align(4))] // Ensure the two lower bits are free to use as state bits.
struct Waiter {
    thread: Cell<Option<Thread>>,
    signaled: AtomicBool,
    next: *mut Waiter,
}

/// Drains and notifies the queue of waiters on drop.
struct Guard<'a> {
    queue: &'a AtomicPtr<Waiter>,
    new_queue: *mut Waiter,
}

impl Drop for Guard<'_> {
    fn drop(&mut self) {
        let queue = self.queue.swap(self.new_queue, Ordering::AcqRel);

        let state = strict::addr(queue) & STATE_MASK;
        assert_eq!(state, RUNNING);

        unsafe {
            let mut waiter = strict::map_addr(queue, |q| q & !STATE_MASK);
            while !waiter.is_null() {
                let next = (*waiter).next;
                let thread = (*waiter).thread.take().unwrap();
                (*waiter).signaled.store(true, Ordering::Release);
                waiter = next;
                thread.unpark();
            }
        }
    }
}

// Corresponds to `std::sync::Once::call_inner`.
//
// Originally copied from std, but since modified to remove poisoning and to
// support wait.
//
// Note: this is intentionally monomorphic
#[inline(never)]
fn initialize_or_wait(queue: &AtomicPtr<Waiter>, mut init: Option<&mut dyn FnMut() -> bool>) {
    let mut curr_queue = queue.load(Ordering::Acquire);

    loop {
        let curr_state = strict::addr(curr_queue) & STATE_MASK;
        match (curr_state, &mut init) {
            (COMPLETE, _) => return,
            (INCOMPLETE, Some(init)) => {
                let exchange = queue.compare_exchange(
                    curr_queue,
                    strict::map_addr(curr_queue, |q| (q & !STATE_MASK) | RUNNING),
                    Ordering::Acquire,
                    Ordering::Acquire,
                );
                if let Err(new_queue) = exchange {
                    curr_queue = new_queue;
                    continue;
                }
                let mut guard = Guard { queue, new_queue: INCOMPLETE_PTR };
                if init() {
                    guard.new_queue = COMPLETE_PTR;
                }
                return;
            }
            (INCOMPLETE, None) | (RUNNING, _) => {
                wait(queue, curr_queue);
                curr_queue = queue.load(Ordering::Acquire);
            }
            _ => debug_assert!(false),
        }
    }
}

fn wait(queue: &AtomicPtr<Waiter>, mut curr_queue: *mut Waiter) {
    let curr_state = strict::addr(curr_queue) & STATE_MASK;
    loop {
        let node = Waiter {
            thread: Cell::new(Some(thread::current())),
            signaled: AtomicBool::new(false),
            next: strict::map_addr(curr_queue, |q| q & !STATE_MASK),
        };
        let me = &node as *const Waiter as *mut Waiter;

        let exchange = queue.compare_exchange(
            curr_queue,
            strict::map_addr(me, |q| q | curr_state),
            Ordering::Release,
            Ordering::Relaxed,
        );
        if let Err(new_queue) = exchange {
            if strict::addr(new_queue) & STATE_MASK != curr_state {
                return;
            }
            curr_queue = new_queue;
            continue;
        }

        while !node.signaled.load(Ordering::Acquire) {
            thread::park();
        }
        break;
    }
}

// Polyfill of strict provenance from https://crates.io/crates/sptr.
//
// Use free-standing function rather than a trait to keep things simple and
// avoid any potential conflicts with future stabile std API.
mod strict {
    #[must_use]
    #[inline]
    pub(crate) fn addr<T>(ptr: *mut T) -> usize
    where
        T: Sized,
    {
        // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
        // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the
        // provenance).
        unsafe { core::mem::transmute(ptr) }
    }

    #[must_use]
    #[inline]
    pub(crate) fn with_addr<T>(ptr: *mut T, addr: usize) -> *mut T
    where
        T: Sized,
    {
        // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
        //
        // In the mean-time, this operation is defined to be "as if" it was
        // a wrapping_offset, so we can emulate it as such. This should properly
        // restore pointer provenance even under today's compiler.
        let self_addr = self::addr(ptr) as isize;
        let dest_addr = addr as isize;
        let offset = dest_addr.wrapping_sub(self_addr);

        // This is the canonical desugarring of this operation,
        // but `pointer::cast` was only stabilized in 1.38.
        // self.cast::<u8>().wrapping_offset(offset).cast::<T>()
        (ptr as *mut u8).wrapping_offset(offset) as *mut T
    }

    #[must_use]
    #[inline]
    pub(crate) fn map_addr<T>(ptr: *mut T, f: impl FnOnce(usize) -> usize) -> *mut T
    where
        T: Sized,
    {
        self::with_addr(ptr, f(addr(ptr)))
    }
}

// These test are snatched from std as well.
#[cfg(test)]
mod tests {
    use std::panic;
    use std::{sync::mpsc::channel, thread};

    use super::OnceCell;

    impl<T> OnceCell<T> {
        fn init(&self, f: impl FnOnce() -> T) {
            enum Void {}
            let _ = self.initialize(|| Ok::<T, Void>(f()));
        }
    }

    #[test]
    fn smoke_once() {
        static O: OnceCell<()> = OnceCell::new();
        let mut a = 0;
        O.init(|| a += 1);
        assert_eq!(a, 1);
        O.init(|| a += 1);
        assert_eq!(a, 1);
    }

    #[test]
    fn stampede_once() {
        static O: OnceCell<()> = OnceCell::new();
        static mut RUN: bool = false;

        let (tx, rx) = channel();
        for _ in 0..10 {
            let tx = tx.clone();
            thread::spawn(move || {
                for _ in 0..4 {
                    thread::yield_now()
                }
                unsafe {
                    O.init(|| {
                        assert!(!RUN);
                        RUN = true;
                    });
                    assert!(RUN);
                }
                tx.send(()).unwrap();
            });
        }

        unsafe {
            O.init(|| {
                assert!(!RUN);
                RUN = true;
            });
            assert!(RUN);
        }

        for _ in 0..10 {
            rx.recv().unwrap();
        }
    }

    #[test]
    fn poison_bad() {
        static O: OnceCell<()> = OnceCell::new();

        // poison the once
        let t = panic::catch_unwind(|| {
            O.init(|| panic!());
        });
        assert!(t.is_err());

        // we can subvert poisoning, however
        let mut called = false;
        O.init(|| {
            called = true;
        });
        assert!(called);

        // once any success happens, we stop propagating the poison
        O.init(|| {});
    }

    #[test]
    fn wait_for_force_to_finish() {
        static O: OnceCell<()> = OnceCell::new();

        // poison the once
        let t = panic::catch_unwind(|| {
            O.init(|| panic!());
        });
        assert!(t.is_err());

        // make sure someone's waiting inside the once via a force
        let (tx1, rx1) = channel();
        let (tx2, rx2) = channel();
        let t1 = thread::spawn(move || {
            O.init(|| {
                tx1.send(()).unwrap();
                rx2.recv().unwrap();
            });
        });

        rx1.recv().unwrap();

        // put another waiter on the once
        let t2 = thread::spawn(|| {
            let mut called = false;
            O.init(|| {
                called = true;
            });
            assert!(!called);
        });

        tx2.send(()).unwrap();

        assert!(t1.join().is_ok());
        assert!(t2.join().is_ok());
    }

    #[test]
    #[cfg(target_pointer_width = "64")]
    fn test_size() {
        use std::mem::size_of;

        assert_eq!(size_of::<OnceCell<u32>>(), 4 * size_of::<u32>());
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/once_cell-1.19.0/src/lib.rs

Source (jump to first uncovered line)
//! # Overview
//!
//! `once_cell` provides two new cell-like types, [`unsync::OnceCell`] and
//! [`sync::OnceCell`]. A `OnceCell` might store arbitrary non-`Copy` types, can
//! be assigned to at most once and provides direct access to the stored
//! contents. The core API looks *roughly* like this (and there's much more
//! inside, read on!):
//!
//! ```rust,ignore
//! impl<T> OnceCell<T> {
//!     const fn new() -> OnceCell<T> { ... }
//!     fn set(&self, value: T) -> Result<(), T> { ... }
//!     fn get(&self) -> Option<&T> { ... }
//! }
//! ```
//!
//! Note that, like with [`RefCell`] and [`Mutex`], the `set` method requires
//! only a shared reference. Because of the single assignment restriction `get`
//! can return a `&T` instead of `Ref<T>` or `MutexGuard<T>`.
//!
//! The `sync` flavor is thread-safe (that is, implements the [`Sync`] trait),
//! while the `unsync` one is not.
//!
//! [`unsync::OnceCell`]: unsync/struct.OnceCell.html
//! [`sync::OnceCell`]: sync/struct.OnceCell.html
//! [`RefCell`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html
//! [`Mutex`]: https://doc.rust-lang.org/std/sync/struct.Mutex.html
//! [`Sync`]: https://doc.rust-lang.org/std/marker/trait.Sync.html
//!
//! # Recipes
//!
//! `OnceCell` might be useful for a variety of patterns.
//!
//! ## Safe Initialization of Global Data
//!
//! ```rust
//! use std::{env, io};
//!
//! use once_cell::sync::OnceCell;
//!
//! #[derive(Debug)]
//! pub struct Logger {
//!     // ...
//! }
//! static INSTANCE: OnceCell<Logger> = OnceCell::new();
//!
//! impl Logger {
//!     pub fn global() -> &'static Logger {
//!         INSTANCE.get().expect("logger is not initialized")
//!     }
//!
//!     fn from_cli(args: env::Args) -> Result<Logger, std::io::Error> {
//!        // ...
//! #      Ok(Logger {})
//!     }
//! }
//!
//! fn main() {
//!     let logger = Logger::from_cli(env::args()).unwrap();
//!     INSTANCE.set(logger).unwrap();
//!     // use `Logger::global()` from now on
//! }
//! ```
//!
//! ## Lazy Initialized Global Data
//!
//! This is essentially the `lazy_static!` macro, but without a macro.
//!
//! ```rust
//! use std::{sync::Mutex, collections::HashMap};
//!
//! use once_cell::sync::OnceCell;
//!
//! fn global_data() -> &'static Mutex<HashMap<i32, String>> {
//!     static INSTANCE: OnceCell<Mutex<HashMap<i32, String>>> = OnceCell::new();
//!     INSTANCE.get_or_init(|| {
//!         let mut m = HashMap::new();
//!         m.insert(13, "Spica".to_string());
//!         m.insert(74, "Hoyten".to_string());
//!         Mutex::new(m)
//!     })
//! }
//! ```
//!
//! There are also the [`sync::Lazy`] and [`unsync::Lazy`] convenience types to
//! streamline this pattern:
//!
//! ```rust
//! use std::{sync::Mutex, collections::HashMap};
//! use once_cell::sync::Lazy;
//!
//! static GLOBAL_DATA: Lazy<Mutex<HashMap<i32, String>>> = Lazy::new(|| {
//!     let mut m = HashMap::new();
//!     m.insert(13, "Spica".to_string());
//!     m.insert(74, "Hoyten".to_string());
//!     Mutex::new(m)
//! });
//!
//! fn main() {
//!     println!("{:?}", GLOBAL_DATA.lock().unwrap());
//! }
//! ```
//!
//! Note that the variable that holds `Lazy` is declared as `static`, *not*
//! `const`. This is important: using `const` instead compiles, but works wrong.
//!
//! [`sync::Lazy`]: sync/struct.Lazy.html
//! [`unsync::Lazy`]: unsync/struct.Lazy.html
//!
//! ## General purpose lazy evaluation
//!
//! Unlike `lazy_static!`, `Lazy` works with local variables.
//!
//! ```rust
//! use once_cell::unsync::Lazy;
//!
//! fn main() {
//!     let ctx = vec![1, 2, 3];
//!     let thunk = Lazy::new(|| {
//!         ctx.iter().sum::<i32>()
//!     });
//!     assert_eq!(*thunk, 6);
//! }
//! ```
//!
//! If you need a lazy field in a struct, you probably should use `OnceCell`
//! directly, because that will allow you to access `self` during
//! initialization.
//!
//! ```rust
//! use std::{fs, path::PathBuf};
//!
//! use once_cell::unsync::OnceCell;
//!
//! struct Ctx {
//!     config_path: PathBuf,
//!     config: OnceCell<String>,
//! }
//!
//! impl Ctx {
//!     pub fn get_config(&self) -> Result<&str, std::io::Error> {
//!         let cfg = self.config.get_or_try_init(|| {
//!             fs::read_to_string(&self.config_path)
//!         })?;
//!         Ok(cfg.as_str())
//!     }
//! }
//! ```
//!
//! ## Lazily Compiled Regex
//!
//! This is a `regex!` macro which takes a string literal and returns an
//! *expression* that evaluates to a `&'static Regex`:
//!
//! ```
//! macro_rules! regex {
//!     ($re:literal $(,)?) => {{
//!         static RE: once_cell::sync::OnceCell<regex::Regex> = once_cell::sync::OnceCell::new();
//!         RE.get_or_init(|| regex::Regex::new($re).unwrap())
//!     }};
//! }
//! ```
//!
//! This macro can be useful to avoid the "compile regex on every loop
//! iteration" problem.
//!
//! ## Runtime `include_bytes!`
//!
//! The `include_bytes` macro is useful to include test resources, but it slows
//! down test compilation a lot. An alternative is to load the resources at
//! runtime:
//!
//! ```
//! use std::path::Path;
//!
//! use once_cell::sync::OnceCell;
//!
//! pub struct TestResource {
//!     path: &'static str,
//!     cell: OnceCell<Vec<u8>>,
//! }
//!
//! impl TestResource {
//!     pub const fn new(path: &'static str) -> TestResource {
//!         TestResource { path, cell: OnceCell::new() }
//!     }
//!     pub fn bytes(&self) -> &[u8] {
//!         self.cell.get_or_init(|| {
//!             let dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
//!             let path = Path::new(dir.as_str()).join(self.path);
//!             std::fs::read(&path).unwrap_or_else(|_err| {
//!                 panic!("failed to load test resource: {}", path.display())
//!             })
//!         }).as_slice()
//!     }
//! }
//!
//! static TEST_IMAGE: TestResource = TestResource::new("test_data/lena.png");
//!
//! #[test]
//! fn test_sobel_filter() {
//!     let rgb: &[u8] = TEST_IMAGE.bytes();
//!     // ...
//! # drop(rgb);
//! }
//! ```
//!
//! ## `lateinit`
//!
//! `LateInit` type for delayed initialization. It is reminiscent of Kotlin's
//! `lateinit` keyword and allows construction of cyclic data structures:
//!
//!
//! ```
//! use once_cell::sync::OnceCell;
//!
//! pub struct LateInit<T> { cell: OnceCell<T> }
//!
//! impl<T> LateInit<T> {
//!     pub fn init(&self, value: T) {
//!         assert!(self.cell.set(value).is_ok())
//!     }
//! }
//!
//! impl<T> Default for LateInit<T> {
//!     fn default() -> Self { LateInit { cell: OnceCell::default() } }
//! }
//!
//! impl<T> std::ops::Deref for LateInit<T> {
//!     type Target = T;
//!     fn deref(&self) -> &T {
//!         self.cell.get().unwrap()
//!     }
//! }
//!
//! #[derive(Default)]
//! struct A<'a> {
//!     b: LateInit<&'a B<'a>>,
//! }
//!
//! #[derive(Default)]
//! struct B<'a> {
//!     a: LateInit<&'a A<'a>>
//! }
//!
//!
//! fn build_cycle() {
//!     let a = A::default();
//!     let b = B::default();
//!     a.b.init(&b);
//!     b.a.init(&a);
//!
//!     let _a = &a.b.a.b.a;
//! }
//! ```
//!
//! # Comparison with std
//!
//! |`!Sync` types         | Access Mode            | Drawbacks                                     |
//! |----------------------|------------------------|-----------------------------------------------|
//! |`Cell<T>`             | `T`                    | requires `T: Copy` for `get`                  |
//! |`RefCell<T>`          | `RefMut<T>` / `Ref<T>` | may panic at runtime                          |
//! |`unsync::OnceCell<T>` | `&T`                   | assignable only once                          |
//!
//! |`Sync` types          | Access Mode            | Drawbacks                                     |
//! |----------------------|------------------------|-----------------------------------------------|
//! |`AtomicT`             | `T`                    | works only with certain `Copy` types          |
//! |`Mutex<T>`            | `MutexGuard<T>`        | may deadlock at runtime, may block the thread |
//! |`sync::OnceCell<T>`   | `&T`                   | assignable only once, may block the thread    |
//!
//! Technically, calling `get_or_init` will also cause a panic or a deadlock if
//! it recursively calls itself. However, because the assignment can happen only
//! once, such cases should be more rare than equivalents with `RefCell` and
//! `Mutex`.
//!
//! # Minimum Supported `rustc` Version
//!
//! If only the `std`, `alloc`, or `race` features are enabled, MSRV will be
//! updated conservatively, supporting at least latest 8 versions of the compiler.
//! When using other features, like `parking_lot`, MSRV might be updated more
//! frequently, up to the latest stable. In both cases, increasing MSRV is *not*
//! considered a semver-breaking change and requires only a minor version bump.
//!
//! # Implementation details
//!
//! The implementation is based on the
//! [`lazy_static`](https://github.com/rust-lang-nursery/lazy-static.rs/) and
//! [`lazy_cell`](https://github.com/indiv0/lazycell/) crates and
//! [`std::sync::Once`]. In some sense, `once_cell` just streamlines and unifies
//! those APIs.
//!
//! To implement a sync flavor of `OnceCell`, this crates uses either a custom
//! re-implementation of `std::sync::Once` or `parking_lot::Mutex`. This is
//! controlled by the `parking_lot` feature (disabled by default). Performance
//! is the same for both cases, but the `parking_lot` based `OnceCell<T>` is
//! smaller by up to 16 bytes.
//!
//! This crate uses `unsafe`.
//!
//! [`std::sync::Once`]: https://doc.rust-lang.org/std/sync/struct.Once.html
//!
//! # F.A.Q.
//!
//! **Should I use the sync or unsync flavor?**
//!
//! Because Rust compiler checks thread safety for you, it's impossible to
//! accidentally use `unsync` where `sync` is required. So, use `unsync` in
//! single-threaded code and `sync` in multi-threaded. It's easy to switch
//! between the two if code becomes multi-threaded later.
//!
//! At the moment, `unsync` has an additional benefit that reentrant
//! initialization causes a panic, which might be easier to debug than a
//! deadlock.
//!
//! **Does this crate support async?**
//!
//! No, but you can use
//! [`async_once_cell`](https://crates.io/crates/async_once_cell) instead.
//!
//! **Does this crate support `no_std`?**
//!
//! Yes, but with caveats. `OnceCell` is a synchronization primitive which
//! _semantically_ relies on blocking. `OnceCell` guarantees that at most one
//! `f` will be called to compute the value. If two threads of execution call
//! `get_or_init` concurrently, one of them has to wait.
//!
//! Waiting fundamentally requires OS support. Execution environment needs to
//! understand who waits on whom to prevent deadlocks due to priority inversion.
//! You _could_ make code to compile by blindly using pure spinlocks, but the
//! runtime behavior would be subtly wrong.
//!
//! Given these constraints, `once_cell` provides the following options:
//!
//! - The `race` module provides similar, but distinct synchronization primitive
//!   which is compatible with `no_std`. With `race`, the `f` function can be
//!   called multiple times by different threads, but only one thread will win
//!   to install the value.
//! - `critical-section` feature (with a `-`, not `_`) uses `critical_section`
//!   to implement blocking.
//!
//! **Can I bring my own mutex?**
//!
//! There is [generic_once_cell](https://crates.io/crates/generic_once_cell) to
//! allow just that.
//!
//! **Should I use `std::cell::OnceCell`, `once_cell`, or `lazy_static`?**
//!
//! If you can use `std` version (your MSRV is at least 1.70, and you don't need
//! extra features `once_cell` provides), use `std`. Otherwise, use `once_cell`.
//! Don't use `lazy_static`.
//!
//! # Related crates
//!
//! * Most of this crate's functionality is available in `std` starting with
//!   Rust 1.70. See `std::cell::OnceCell` and `std::sync::OnceLock`.
//! * [double-checked-cell](https://github.com/niklasf/double-checked-cell)
//! * [lazy-init](https://crates.io/crates/lazy-init)
//! * [lazycell](https://crates.io/crates/lazycell)
//! * [mitochondria](https://crates.io/crates/mitochondria)
//! * [lazy_static](https://crates.io/crates/lazy_static)
//! * [async_once_cell](https://crates.io/crates/async_once_cell)
//! * [generic_once_cell](https://crates.io/crates/generic_once_cell) (bring
//!   your own mutex)

#![cfg_attr(not(feature = "std"), no_std)]

#[cfg(feature = "alloc")]
extern crate alloc;

#[cfg(all(feature = "critical-section", not(feature = "std")))]
#[path = "imp_cs.rs"]
mod imp;

#[cfg(all(feature = "std", feature = "parking_lot"))]
#[path = "imp_pl.rs"]
mod imp;

#[cfg(all(feature = "std", not(feature = "parking_lot")))]
#[path = "imp_std.rs"]
mod imp;

/// Single-threaded version of `OnceCell`.
pub mod unsync {
    use core::{
        cell::{Cell, UnsafeCell},
        fmt, mem,
        ops::{Deref, DerefMut},
        panic::{RefUnwindSafe, UnwindSafe},
    };

    /// A cell which can be written to only once. It is not thread safe.
    ///
    /// Unlike [`std::cell::RefCell`], a `OnceCell` provides simple `&`
    /// references to the contents.
    ///
    /// [`std::cell::RefCell`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html
    ///
    /// # Example
    /// ```
    /// use once_cell::unsync::OnceCell;
    ///
    /// let cell = OnceCell::new();
    /// assert!(cell.get().is_none());
    ///
    /// let value: &String = cell.get_or_init(|| {
    ///     "Hello, World!".to_string()
    /// });
    /// assert_eq!(value, "Hello, World!");
    /// assert!(cell.get().is_some());
    /// ```
    pub struct OnceCell<T> {
        // Invariant: written to at most once.
        inner: UnsafeCell<Option<T>>,
    }

    // Similarly to a `Sync` bound on `sync::OnceCell`, we can use
    // `&unsync::OnceCell` to sneak a `T` through `catch_unwind`,
    // by initializing the cell in closure and extracting the value in the
    // `Drop`.
    impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceCell<T> {}
    impl<T: UnwindSafe> UnwindSafe for OnceCell<T> {}

    impl<T> Default for OnceCell<T> {
        fn default() -> Self {
            Self::new()
        }
    }

    impl<T: fmt::Debug> fmt::Debug for OnceCell<T> {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            match self.get() {
                Some(v) => f.debug_tuple("OnceCell").field(v).finish(),
                None => f.write_str("OnceCell(Uninit)"),
            }
        }
    }

    impl<T: Clone> Clone for OnceCell<T> {
        fn clone(&self) -> OnceCell<T> {
            match self.get() {
                Some(value) => OnceCell::with_value(value.clone()),
                None => OnceCell::new(),
            }
        }

        fn clone_from(&mut self, source: &Self) {
            match (self.get_mut(), source.get()) {
                (Some(this), Some(source)) => this.clone_from(source),
                _ => *self = source.clone(),
            }
        }
    }

    impl<T: PartialEq> PartialEq for OnceCell<T> {
        fn eq(&self, other: &Self) -> bool {
            self.get() == other.get()
        }
    }

    impl<T: Eq> Eq for OnceCell<T> {}

    impl<T> From<T> for OnceCell<T> {
        fn from(value: T) -> Self {
            OnceCell::with_value(value)
        }
    }

    impl<T> OnceCell<T> {
        /// Creates a new empty cell.
        pub const fn new() -> OnceCell<T> {
            OnceCell { inner: UnsafeCell::new(None) }
        }

        /// Creates a new initialized cell.
        pub const fn with_value(value: T) -> OnceCell<T> {
            OnceCell { inner: UnsafeCell::new(Some(value)) }
        }

        /// Gets a reference to the underlying value.
        ///
        /// Returns `None` if the cell is empty.
        #[inline]
        pub fn get(&self) -> Option<&T> {
            // Safe due to `inner`'s invariant of being written to at most once.
            // Had multiple writes to `inner` been allowed, a reference to the
            // value we return now would become dangling by a write of a
            // different value later.
            unsafe { &*self.inner.get() }.as_ref()
        }

        /// Gets a mutable reference to the underlying value.
        ///
        /// Returns `None` if the cell is empty.
        ///
        /// This method is allowed to violate the invariant of writing to a `OnceCell`
        /// at most once because it requires `&mut` access to `self`. As with all
        /// interior mutability, `&mut` access permits arbitrary modification:
        ///
        /// ```
        /// use once_cell::unsync::OnceCell;
        ///
        /// let mut cell: OnceCell<u32> = OnceCell::new();
        /// cell.set(92).unwrap();
        /// *cell.get_mut().unwrap() = 93;
        /// assert_eq!(cell.get(), Some(&93));
        /// ```
        #[inline]
        pub fn get_mut(&mut self) -> Option<&mut T> {
            // Safe because we have unique access
            unsafe { &mut *self.inner.get() }.as_mut()
        }

        /// Sets the contents of this cell to `value`.
        ///
        /// Returns `Ok(())` if the cell was empty and `Err(value)` if it was
        /// full.
        ///
        /// # Example
        /// ```
        /// use once_cell::unsync::OnceCell;
        ///
        /// let cell = OnceCell::new();
        /// assert!(cell.get().is_none());
        ///
        /// assert_eq!(cell.set(92), Ok(()));
        /// assert_eq!(cell.set(62), Err(62));
        ///
        /// assert!(cell.get().is_some());
        /// ```
        pub fn set(&self, value: T) -> Result<(), T> {
            match self.try_insert(value) {
                Ok(_) => Ok(()),
                Err((_, value)) => Err(value),
            }
        }

        /// Like [`set`](Self::set), but also returns a reference to the final cell value.
        ///
        /// # Example
        /// ```
        /// use once_cell::unsync::OnceCell;
        ///
        /// let cell = OnceCell::new();
        /// assert!(cell.get().is_none());
        ///
        /// assert_eq!(cell.try_insert(92), Ok(&92));
        /// assert_eq!(cell.try_insert(62), Err((&92, 62)));
        ///
        /// assert!(cell.get().is_some());
        /// ```
        pub fn try_insert(&self, value: T) -> Result<&T, (&T, T)> {
            if let Some(old) = self.get() {
                return Err((old, value));
            }

            let slot = unsafe { &mut *self.inner.get() };
            // This is the only place where we set the slot, no races
            // due to reentrancy/concurrency are possible, and we've
            // checked that slot is currently `None`, so this write
            // maintains the `inner`'s invariant.
            *slot = Some(value);
            Ok(unsafe { slot.as_ref().unwrap_unchecked() })
        }

        /// Gets the contents of the cell, initializing it with `f`
        /// if the cell was empty.
        ///
        /// # Panics
        ///
        /// If `f` panics, the panic is propagated to the caller, and the cell
        /// remains uninitialized.
        ///
        /// It is an error to reentrantly initialize the cell from `f`. Doing
        /// so results in a panic.
        ///
        /// # Example
        /// ```
        /// use once_cell::unsync::OnceCell;
        ///
        /// let cell = OnceCell::new();
        /// let value = cell.get_or_init(|| 92);
        /// assert_eq!(value, &92);
        /// let value = cell.get_or_init(|| unreachable!());
        /// assert_eq!(value, &92);
        /// ```
        pub fn get_or_init<F>(&self, f: F) -> &T
        where
            F: FnOnce() -> T,
        {
            enum Void {}
            match self.get_or_try_init(|| Ok::<T, Void>(f())) {
                Ok(val) => val,
                Err(void) => match void {},
            }
        }

        /// Gets the contents of the cell, initializing it with `f` if
        /// the cell was empty. If the cell was empty and `f` failed, an
        /// error is returned.
        ///
        /// # Panics
        ///
        /// If `f` panics, the panic is propagated to the caller, and the cell
        /// remains uninitialized.
        ///
        /// It is an error to reentrantly initialize the cell from `f`. Doing
        /// so results in a panic.
        ///
        /// # Example
        /// ```
        /// use once_cell::unsync::OnceCell;
        ///
        /// let cell = OnceCell::new();
        /// assert_eq!(cell.get_or_try_init(|| Err(())), Err(()));
        /// assert!(cell.get().is_none());
        /// let value = cell.get_or_try_init(|| -> Result<i32, ()> {
        ///     Ok(92)
        /// });
        /// assert_eq!(value, Ok(&92));
        /// assert_eq!(cell.get(), Some(&92))
        /// ```
        pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E>
        where
            F: FnOnce() -> Result<T, E>,
        {
            if let Some(val) = self.get() {
                return Ok(val);
            }
            let val = f()?;
            // Note that *some* forms of reentrant initialization might lead to
            // UB (see `reentrant_init` test). I believe that just removing this
            // `assert`, while keeping `set/get` would be sound, but it seems
            // better to panic, rather than to silently use an old value.
            assert!(self.set(val).is_ok(), "reentrant init");
            Ok(unsafe { self.get().unwrap_unchecked() })
        }

        /// Takes the value out of this `OnceCell`, moving it back to an uninitialized state.
        ///
        /// Has no effect and returns `None` if the `OnceCell` hasn't been initialized.
        ///
        /// # Examples
        ///
        /// ```
        /// use once_cell::unsync::OnceCell;
        ///
        /// let mut cell: OnceCell<String> = OnceCell::new();
        /// assert_eq!(cell.take(), None);
        ///
        /// let mut cell = OnceCell::new();
        /// cell.set("hello".to_string()).unwrap();
        /// assert_eq!(cell.take(), Some("hello".to_string()));
        /// assert_eq!(cell.get(), None);
        /// ```
        ///
        /// This method is allowed to violate the invariant of writing to a `OnceCell`
        /// at most once because it requires `&mut` access to `self`. As with all
        /// interior mutability, `&mut` access permits arbitrary modification:
        ///
        /// ```
        /// use once_cell::unsync::OnceCell;
        ///
        /// let mut cell: OnceCell<u32> = OnceCell::new();
        /// cell.set(92).unwrap();
        /// cell = OnceCell::new();
        /// ```
        pub fn take(&mut self) -> Option<T> {
            mem::take(self).into_inner()
        }

        /// Consumes the `OnceCell`, returning the wrapped value.
        ///
        /// Returns `None` if the cell was empty.
        ///
        /// # Examples
        ///
        /// ```
        /// use once_cell::unsync::OnceCell;
        ///
        /// let cell: OnceCell<String> = OnceCell::new();
        /// assert_eq!(cell.into_inner(), None);
        ///
        /// let cell = OnceCell::new();
        /// cell.set("hello".to_string()).unwrap();
        /// assert_eq!(cell.into_inner(), Some("hello".to_string()));
        /// ```
        pub fn into_inner(self) -> Option<T> {
            // Because `into_inner` takes `self` by value, the compiler statically verifies
            // that it is not currently borrowed. So it is safe to move out `Option<T>`.
            self.inner.into_inner()
        }
    }

    /// A value which is initialized on the first access.
    ///
    /// # Example
    /// ```
    /// use once_cell::unsync::Lazy;
    ///
    /// let lazy: Lazy<i32> = Lazy::new(|| {
    ///     println!("initializing");
    ///     92
    /// });
    /// println!("ready");
    /// println!("{}", *lazy);
    /// println!("{}", *lazy);
    ///
    /// // Prints:
    /// //   ready
    /// //   initializing
    /// //   92
    /// //   92
    /// ```
    pub struct Lazy<T, F = fn() -> T> {
        cell: OnceCell<T>,
        init: Cell<Option<F>>,
    }

    impl<T, F: RefUnwindSafe> RefUnwindSafe for Lazy<T, F> where OnceCell<T>: RefUnwindSafe {}

    impl<T: fmt::Debug, F> fmt::Debug for Lazy<T, F> {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            f.debug_struct("Lazy").field("cell", &self.cell).field("init", &"..").finish()
        }
    }

    impl<T, F> Lazy<T, F> {
        /// Creates a new lazy value with the given initializing function.
        ///
        /// # Example
        /// ```
        /// # fn main() {
        /// use once_cell::unsync::Lazy;
        ///
        /// let hello = "Hello, World!".to_string();
        ///
        /// let lazy = Lazy::new(|| hello.to_uppercase());
        ///
        /// assert_eq!(&*lazy, "HELLO, WORLD!");
        /// # }
        /// ```
        pub const fn new(init: F) -> Lazy<T, F> {
            Lazy { cell: OnceCell::new(), init: Cell::new(Some(init)) }
        }

        /// Consumes this `Lazy` returning the stored value.
        ///
        /// Returns `Ok(value)` if `Lazy` is initialized and `Err(f)` otherwise.
        pub fn into_value(this: Lazy<T, F>) -> Result<T, F> {
            let cell = this.cell;
            let init = this.init;
            cell.into_inner().ok_or_else(|| {
                init.take().unwrap_or_else(|| panic!("Lazy instance has previously been poisoned"))
            })
        }
    }

    impl<T, F: FnOnce() -> T> Lazy<T, F> {
        /// Forces the evaluation of this lazy value and returns a reference to
        /// the result.
        ///
        /// This is equivalent to the `Deref` impl, but is explicit.
        ///
        /// # Example
        /// ```
        /// use once_cell::unsync::Lazy;
        ///
        /// let lazy = Lazy::new(|| 92);
        ///
        /// assert_eq!(Lazy::force(&lazy), &92);
        /// assert_eq!(&*lazy, &92);
        /// ```
        pub fn force(this: &Lazy<T, F>) -> &T {
            this.cell.get_or_init(|| match this.init.take() {
                Some(f) => f(),
                None => panic!("Lazy instance has previously been poisoned"),
            })
        }

        /// Forces the evaluation of this lazy value and returns a mutable reference to
        /// the result.
        ///
        /// This is equivalent to the `DerefMut` impl, but is explicit.
        ///
        /// # Example
        /// ```
        /// use once_cell::unsync::Lazy;
        ///
        /// let mut lazy = Lazy::new(|| 92);
        ///
        /// assert_eq!(Lazy::force_mut(&mut lazy), &92);
        /// assert_eq!(*lazy, 92);
        /// ```
        pub fn force_mut(this: &mut Lazy<T, F>) -> &mut T {
            if this.cell.get_mut().is_none() {
                let value = match this.init.get_mut().take() {
                    Some(f) => f(),
                    None => panic!("Lazy instance has previously been poisoned"),
                };
                this.cell = OnceCell::with_value(value);
            }
            this.cell.get_mut().unwrap_or_else(|| unreachable!())
        }

        /// Gets the reference to the result of this lazy value if
        /// it was initialized, otherwise returns `None`.
        ///
        /// # Example
        /// ```
        /// use once_cell::unsync::Lazy;
        ///
        /// let lazy = Lazy::new(|| 92);
        ///
        /// assert_eq!(Lazy::get(&lazy), None);
        /// assert_eq!(&*lazy, &92);
        /// assert_eq!(Lazy::get(&lazy), Some(&92));
        /// ```
        pub fn get(this: &Lazy<T, F>) -> Option<&T> {
            this.cell.get()
        }

        /// Gets the mutable reference to the result of this lazy value if
        /// it was initialized, otherwise returns `None`.
        ///
        /// # Example
        /// ```
        /// use once_cell::unsync::Lazy;
        ///
        /// let mut lazy = Lazy::new(|| 92);
        ///
        /// assert_eq!(Lazy::get_mut(&mut lazy), None);
        /// assert_eq!(*lazy, 92);
        /// assert_eq!(Lazy::get_mut(&mut lazy), Some(&mut 92));
        /// ```
        pub fn get_mut(this: &mut Lazy<T, F>) -> Option<&mut T> {
            this.cell.get_mut()
        }
    }

    impl<T, F: FnOnce() -> T> Deref for Lazy<T, F> {
        type Target = T;
        fn deref(&self) -> &T {
            Lazy::force(self)
        }
    }

    impl<T, F: FnOnce() -> T> DerefMut for Lazy<T, F> {
        fn deref_mut(&mut self) -> &mut T {
            Lazy::force_mut(self)
        }
    }

    impl<T: Default> Default for Lazy<T> {
        /// Creates a new lazy value using `Default` as the initializing function.
        fn default() -> Lazy<T> {
            Lazy::new(T::default)
        }
    }
}

/// Thread-safe, blocking version of `OnceCell`.
#[cfg(any(feature = "std", feature = "critical-section"))]
pub mod sync {
    use core::{
        cell::Cell,
        fmt, mem,
        ops::{Deref, DerefMut},
        panic::RefUnwindSafe,
    };

    use super::imp::OnceCell as Imp;

    /// A thread-safe cell which can be written to only once.
    ///
    /// `OnceCell` provides `&` references to the contents without RAII guards.
    ///
    /// Reading a non-`None` value out of `OnceCell` establishes a
    /// happens-before relationship with a corresponding write. For example, if
    /// thread A initializes the cell with `get_or_init(f)`, and thread B
    /// subsequently reads the result of this call, B also observes all the side
    /// effects of `f`.
    ///
    /// # Example
    /// ```
    /// use once_cell::sync::OnceCell;
    ///
    /// static CELL: OnceCell<String> = OnceCell::new();
    /// assert!(CELL.get().is_none());
    ///
    /// std::thread::spawn(|| {
    ///     let value: &String = CELL.get_or_init(|| {
    ///         "Hello, World!".to_string()
    ///     });
    ///     assert_eq!(value, "Hello, World!");
    /// }).join().unwrap();
    ///
    /// let value: Option<&String> = CELL.get();
    /// assert!(value.is_some());
    /// assert_eq!(value.unwrap().as_str(), "Hello, World!");
    /// ```
    pub struct OnceCell<T>(Imp<T>);

    impl<T> Default for OnceCell<T> {
        fn default() -> OnceCell<T> {
            OnceCell::new()
        }
    }

    impl<T: fmt::Debug> fmt::Debug for OnceCell<T> {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            match self.get() {
                Some(v) => f.debug_tuple("OnceCell").field(v).finish(),
                None => f.write_str("OnceCell(Uninit)"),
            }
        }
    }

    impl<T: Clone> Clone for OnceCell<T> {
        fn clone(&self) -> OnceCell<T> {
            match self.get() {
                Some(value) => Self::with_value(value.clone()),
                None => Self::new(),
            }
        }

        fn clone_from(&mut self, source: &Self) {
            match (self.get_mut(), source.get()) {
                (Some(this), Some(source)) => this.clone_from(source),
                _ => *self = source.clone(),
            }
        }
    }

    impl<T> From<T> for OnceCell<T> {
        fn from(value: T) -> Self {
            Self::with_value(value)
        }
    }

    impl<T: PartialEq> PartialEq for OnceCell<T> {
        fn eq(&self, other: &OnceCell<T>) -> bool {
            self.get() == other.get()
        }
    }

    impl<T: Eq> Eq for OnceCell<T> {}

    impl<T> OnceCell<T> {
        /// Creates a new empty cell.
        pub const fn new() -> OnceCell<T> {
            OnceCell(Imp::new())
        }

        /// Creates a new initialized cell.
        pub const fn with_value(value: T) -> OnceCell<T> {
            OnceCell(Imp::with_value(value))
        }

        /// Gets the reference to the underlying value.
        ///
        /// Returns `None` if the cell is empty, or being initialized. This
        /// method never blocks.
        pub fn get(&self) -> Option<&T> {
            if self.0.is_initialized() {
                // Safe b/c value is initialized.
                Some(unsafe { self.get_unchecked() })
            } else {
                None
            }
        }

        /// Gets the reference to the underlying value, blocking the current
        /// thread until it is set.
        ///
        /// ```
        /// use once_cell::sync::OnceCell;
        ///
        /// let mut cell = std::sync::Arc::new(OnceCell::new());
        /// let t = std::thread::spawn({
        ///     let cell = std::sync::Arc::clone(&cell);
        ///     move || cell.set(92).unwrap()
        /// });
        ///
        /// // Returns immediately, but might return None.
        /// let _value_or_none = cell.get();
        ///
        /// // Will return 92, but might block until the other thread does `.set`.
        /// let value: &u32 = cell.wait();
        /// assert_eq!(*value, 92);
        /// t.join().unwrap();
        /// ```
        #[cfg(feature = "std")]
        pub fn wait(&self) -> &T {
            if !self.0.is_initialized() {
                self.0.wait()
            }
            debug_assert!(self.0.is_initialized());
            // Safe b/c of the wait call above and the fact that we didn't
            // relinquish our borrow.
            unsafe { self.get_unchecked() }
        }

        /// Gets the mutable reference to the underlying value.
        ///
        /// Returns `None` if the cell is empty.
        ///
        /// This method is allowed to violate the invariant of writing to a `OnceCell`
        /// at most once because it requires `&mut` access to `self`. As with all
        /// interior mutability, `&mut` access permits arbitrary modification:
        ///
        /// ```
        /// use once_cell::sync::OnceCell;
        ///
        /// let mut cell: OnceCell<u32> = OnceCell::new();
        /// cell.set(92).unwrap();
        /// cell = OnceCell::new();
        /// ```
        #[inline]
        pub fn get_mut(&mut self) -> Option<&mut T> {
            self.0.get_mut()
        }

        /// Get the reference to the underlying value, without checking if the
        /// cell is initialized.
        ///
        /// # Safety
        ///
        /// Caller must ensure that the cell is in initialized state, and that
        /// the contents are acquired by (synchronized to) this thread.
        #[inline]
        pub unsafe fn get_unchecked(&self) -> &T {
            self.0.get_unchecked()
        }

        /// Sets the contents of this cell to `value`.
        ///
        /// Returns `Ok(())` if the cell was empty and `Err(value)` if it was
        /// full.
        ///
        /// # Example
        ///
        /// ```
        /// use once_cell::sync::OnceCell;
        ///
        /// static CELL: OnceCell<i32> = OnceCell::new();
        ///
        /// fn main() {
        ///     assert!(CELL.get().is_none());
        ///
        ///     std::thread::spawn(|| {
        ///         assert_eq!(CELL.set(92), Ok(()));
        ///     }).join().unwrap();
        ///
        ///     assert_eq!(CELL.set(62), Err(62));
        ///     assert_eq!(CELL.get(), Some(&92));
        /// }
        /// ```
        pub fn set(&self, value: T) -> Result<(), T> {
            match self.try_insert(value) {
                Ok(_) => Ok(()),
                Err((_, value)) => Err(value),
            }
        }

        /// Like [`set`](Self::set), but also returns a reference to the final cell value.
        ///
        /// # Example
        ///
        /// ```
        /// use once_cell::unsync::OnceCell;
        ///
        /// let cell = OnceCell::new();
        /// assert!(cell.get().is_none());
        ///
        /// assert_eq!(cell.try_insert(92), Ok(&92));
        /// assert_eq!(cell.try_insert(62), Err((&92, 62)));
        ///
        /// assert!(cell.get().is_some());
        /// ```
        pub fn try_insert(&self, value: T) -> Result<&T, (&T, T)> {
            let mut value = Some(value);
            let res = self.get_or_init(|| unsafe { value.take().unwrap_unchecked() });
            match value {
                None => Ok(res),
                Some(value) => Err((res, value)),
            }
        }

        /// Gets the contents of the cell, initializing it with `f` if the cell
        /// was empty.
        ///
        /// Many threads may call `get_or_init` concurrently with different
        /// initializing functions, but it is guaranteed that only one function
        /// will be executed.
        ///
        /// # Panics
        ///
        /// If `f` panics, the panic is propagated to the caller, and the cell
        /// remains uninitialized.
        ///
        /// It is an error to reentrantly initialize the cell from `f`. The
        /// exact outcome is unspecified. Current implementation deadlocks, but
        /// this may be changed to a panic in the future.
        ///
        /// # Example
        /// ```
        /// use once_cell::sync::OnceCell;
        ///
        /// let cell = OnceCell::new();
        /// let value = cell.get_or_init(|| 92);
        /// assert_eq!(value, &92);
        /// let value = cell.get_or_init(|| unreachable!());
        /// assert_eq!(value, &92);
        /// ```
        pub fn get_or_init<F>(&self, f: F) -> &T
        where
            F: FnOnce() -> T,
        {
            enum Void {}
            match self.get_or_try_init(|| Ok::<T, Void>(f())) {
                Ok(val) => val,
                Err(void) => match void {},
            }
        }

        /// Gets the contents of the cell, initializing it with `f` if
        /// the cell was empty. If the cell was empty and `f` failed, an
        /// error is returned.
        ///
        /// # Panics
        ///
        /// If `f` panics, the panic is propagated to the caller, and
        /// the cell remains uninitialized.
        ///
        /// It is an error to reentrantly initialize the cell from `f`.
        /// The exact outcome is unspecified. Current implementation
        /// deadlocks, but this may be changed to a panic in the future.
        ///
        /// # Example
        /// ```
        /// use once_cell::sync::OnceCell;
        ///
        /// let cell = OnceCell::new();
        /// assert_eq!(cell.get_or_try_init(|| Err(())), Err(()));
        /// assert!(cell.get().is_none());
        /// let value = cell.get_or_try_init(|| -> Result<i32, ()> {
        ///     Ok(92)
        /// });
        /// assert_eq!(value, Ok(&92));
        /// assert_eq!(cell.get(), Some(&92))
        /// ```
        pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E>
        where
            F: FnOnce() -> Result<T, E>,
        {
            // Fast path check
            if let Some(value) = self.get() {
                return Ok(value);
            }

            self.0.initialize(f)?;

            // Safe b/c value is initialized.
            debug_assert!(self.0.is_initialized());
            Ok(unsafe { self.get_unchecked() })
        }

        /// Takes the value out of this `OnceCell`, moving it back to an uninitialized state.
        ///
        /// Has no effect and returns `None` if the `OnceCell` hasn't been initialized.
        ///
        /// # Examples
        ///
        /// ```
        /// use once_cell::sync::OnceCell;
        ///
        /// let mut cell: OnceCell<String> = OnceCell::new();
        /// assert_eq!(cell.take(), None);
        ///
        /// let mut cell = OnceCell::new();
        /// cell.set("hello".to_string()).unwrap();
        /// assert_eq!(cell.take(), Some("hello".to_string()));
        /// assert_eq!(cell.get(), None);
        /// ```
        ///
        /// This method is allowed to violate the invariant of writing to a `OnceCell`
        /// at most once because it requires `&mut` access to `self`. As with all
        /// interior mutability, `&mut` access permits arbitrary modification:
        ///
        /// ```
        /// use once_cell::sync::OnceCell;
        ///
        /// let mut cell: OnceCell<u32> = OnceCell::new();
        /// cell.set(92).unwrap();
        /// cell = OnceCell::new();
        /// ```
        pub fn take(&mut self) -> Option<T> {
            mem::take(self).into_inner()
        }

        /// Consumes the `OnceCell`, returning the wrapped value. Returns
        /// `None` if the cell was empty.
        ///
        /// # Examples
        ///
        /// ```
        /// use once_cell::sync::OnceCell;
        ///
        /// let cell: OnceCell<String> = OnceCell::new();
        /// assert_eq!(cell.into_inner(), None);
        ///
        /// let cell = OnceCell::new();
        /// cell.set("hello".to_string()).unwrap();
        /// assert_eq!(cell.into_inner(), Some("hello".to_string()));
        /// ```
        #[inline]
        pub fn into_inner(self) -> Option<T> {
            self.0.into_inner()
        }
    }

    /// A value which is initialized on the first access.
    ///
    /// This type is thread-safe and can be used in statics.
    ///
    /// # Example
    ///
    /// ```
    /// use std::collections::HashMap;
    ///
    /// use once_cell::sync::Lazy;
    ///
    /// static HASHMAP: Lazy<HashMap<i32, String>> = Lazy::new(|| {
    ///     println!("initializing");
    ///     let mut m = HashMap::new();
    ///     m.insert(13, "Spica".to_string());
    ///     m.insert(74, "Hoyten".to_string());
    ///     m
    /// });
    ///
    /// fn main() {
    ///     println!("ready");
    ///     std::thread::spawn(|| {
    ///         println!("{:?}", HASHMAP.get(&13));
    ///     }).join().unwrap();
    ///     println!("{:?}", HASHMAP.get(&74));
    ///
    ///     // Prints:
    ///     //   ready
    ///     //   initializing
    ///     //   Some("Spica")
    ///     //   Some("Hoyten")
    /// }
    /// ```
    pub struct Lazy<T, F = fn() -> T> {
        cell: OnceCell<T>,
        init: Cell<Option<F>>,
    }

    impl<T: fmt::Debug, F> fmt::Debug for Lazy<T, F> {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            f.debug_struct("Lazy").field("cell", &self.cell).field("init", &"..").finish()
        }
    }

    // We never create a `&F` from a `&Lazy<T, F>` so it is fine to not impl
    // `Sync` for `F`. We do create a `&mut Option<F>` in `force`, but this is
    // properly synchronized, so it only happens once so it also does not
    // contribute to this impl.
    unsafe impl<T, F: Send> Sync for Lazy<T, F> where OnceCell<T>: Sync {}
    // auto-derived `Send` impl is OK.

    impl<T, F: RefUnwindSafe> RefUnwindSafe for Lazy<T, F> where OnceCell<T>: RefUnwindSafe {}

    impl<T, F> Lazy<T, F> {
        /// Creates a new lazy value with the given initializing
        /// function.
        pub const fn new(f: F) -> Lazy<T, F> {
            Lazy { cell: OnceCell::new(), init: Cell::new(Some(f)) }
        }

        /// Consumes this `Lazy` returning the stored value.
        ///
        /// Returns `Ok(value)` if `Lazy` is initialized and `Err(f)` otherwise.
        pub fn into_value(this: Lazy<T, F>) -> Result<T, F> {
            let cell = this.cell;
            let init = this.init;
            cell.into_inner().ok_or_else(|| {
                init.take().unwrap_or_else(|| panic!("Lazy instance has previously been poisoned"))
            })
        }
    }

    impl<T, F: FnOnce() -> T> Lazy<T, F> {
        /// Forces the evaluation of this lazy value and
        /// returns a reference to the result. This is equivalent
        /// to the `Deref` impl, but is explicit.
        ///
        /// # Example
        /// ```
        /// use once_cell::sync::Lazy;
        ///
        /// let lazy = Lazy::new(|| 92);
        ///
        /// assert_eq!(Lazy::force(&lazy), &92);
        /// assert_eq!(&*lazy, &92);
        /// ```
        pub fn force(this: &Lazy<T, F>) -> &T {
            this.cell.get_or_init(|| match this.init.take() {
                Some(f) => f(),
                None => panic!("Lazy instance has previously been poisoned"),
            })
        }

        /// Forces the evaluation of this lazy value and
        /// returns a mutable reference to the result. This is equivalent
        /// to the `Deref` impl, but is explicit.
        ///
        /// # Example
        /// ```
        /// use once_cell::sync::Lazy;
        ///
        /// let mut lazy = Lazy::new(|| 92);
        ///
        /// assert_eq!(Lazy::force_mut(&mut lazy), &mut 92);
        /// ```
        pub fn force_mut(this: &mut Lazy<T, F>) -> &mut T {
            if this.cell.get_mut().is_none() {
                let value = match this.init.get_mut().take() {
                    Some(f) => f(),
                    None => panic!("Lazy instance has previously been poisoned"),
                };
                this.cell = OnceCell::with_value(value);
            }
            this.cell.get_mut().unwrap_or_else(|| unreachable!())
        }

        /// Gets the reference to the result of this lazy value if
        /// it was initialized, otherwise returns `None`.
        ///
        /// # Example
        /// ```
        /// use once_cell::sync::Lazy;
        ///
        /// let lazy = Lazy::new(|| 92);
        ///
        /// assert_eq!(Lazy::get(&lazy), None);
        /// assert_eq!(&*lazy, &92);
        /// assert_eq!(Lazy::get(&lazy), Some(&92));
        /// ```
        pub fn get(this: &Lazy<T, F>) -> Option<&T> {
            this.cell.get()
        }

        /// Gets the reference to the result of this lazy value if
        /// it was initialized, otherwise returns `None`.
        ///
        /// # Example
        /// ```
        /// use once_cell::sync::Lazy;
        ///
        /// let mut lazy = Lazy::new(|| 92);
        ///
        /// assert_eq!(Lazy::get_mut(&mut lazy), None);
        /// assert_eq!(&*lazy, &92);
        /// assert_eq!(Lazy::get_mut(&mut lazy), Some(&mut 92));
        /// ```
        pub fn get_mut(this: &mut Lazy<T, F>) -> Option<&mut T> {
            this.cell.get_mut()
        }
    }

    impl<T, F: FnOnce() -> T> Deref for Lazy<T, F> {
        type Target = T;
        fn deref(&self) -> &T {
            Lazy::force(self)
        }
    }

    impl<T, F: FnOnce() -> T> DerefMut for Lazy<T, F> {
        fn deref_mut(&mut self) -> &mut T {
            Lazy::force_mut(self)
        }
    }

    impl<T: Default> Default for Lazy<T> {
        /// Creates a new lazy value using `Default` as the initializing function.
        fn default() -> Lazy<T> {
            Lazy::new(T::default)
        }
    }

    /// ```compile_fail
    /// struct S(*mut ());
    /// unsafe impl Sync for S {}
    ///
    /// fn share<T: Sync>(_: &T) {}
    /// share(&once_cell::sync::OnceCell::<S>::new());
    /// ```
    ///
    /// ```compile_fail
    /// struct S(*mut ());
    /// unsafe impl Sync for S {}
    ///
    /// fn share<T: Sync>(_: &T) {}
    /// share(&once_cell::sync::Lazy::<S>::new(|| unimplemented!()));
    /// ```
    fn _dummy() {}
}

#[cfg(feature = "race")]
pub mod race;

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/once_cell-1.19.0/src/race.rs

Source (jump to first uncovered line)
//! Thread-safe, non-blocking, "first one wins" flavor of `OnceCell`.
//!
//! If two threads race to initialize a type from the `race` module, they
//! don't block, execute initialization function together, but only one of
//! them stores the result.
//!
//! This module does not require `std` feature.
//!
//! # Atomic orderings
//!
//! All types in this module use `Acquire` and `Release`
//! [atomic orderings](Ordering) for all their operations. While this is not
//! strictly necessary for types other than `OnceBox`, it is useful for users as
//! it allows them to be certain that after `get` or `get_or_init` returns on
//! one thread, any side-effects caused by the setter thread prior to them
//! calling `set` or `get_or_init` will be made visible to that thread; without
//! it, it's possible for it to appear as if they haven't happened yet from the
//! getter thread's perspective. This is an acceptable tradeoff to make since
//! `Acquire` and `Release` have very little performance overhead on most
//! architectures versus `Relaxed`.

#[cfg(feature = "critical-section")]
use portable_atomic as atomic;
#[cfg(not(feature = "critical-section"))]
use core::sync::atomic;

use atomic::{AtomicPtr, AtomicUsize, Ordering};
use core::cell::UnsafeCell;
use core::marker::PhantomData;
use core::num::NonZeroUsize;
use core::ptr;

/// A thread-safe cell which can be written to only once.
#[derive(Default, Debug)]
pub struct OnceNonZeroUsize {
    inner: AtomicUsize,
}

impl OnceNonZeroUsize {
    /// Creates a new empty cell.
    #[inline]
    pub const fn new() -> OnceNonZeroUsize {
        OnceNonZeroUsize { inner: AtomicUsize::new(0) }
    }

    /// Gets the underlying value.
    #[inline]
    pub fn get(&self) -> Option<NonZeroUsize> {
        let val = self.inner.load(Ordering::Acquire);
        NonZeroUsize::new(val)
    }

    /// Sets the contents of this cell to `value`.
    ///
    /// Returns `Ok(())` if the cell was empty and `Err(())` if it was
    /// full.
    #[inline]
    pub fn set(&self, value: NonZeroUsize) -> Result<(), ()> {
        let exchange =
            self.inner.compare_exchange(0, value.get(), Ordering::AcqRel, Ordering::Acquire);
        match exchange {
            Ok(_) => Ok(()),
            Err(_) => Err(()),
        }
    }

    /// Gets the contents of the cell, initializing it with `f` if the cell was
    /// empty.
    ///
    /// If several threads concurrently run `get_or_init`, more than one `f` can
    /// be called. However, all threads will return the same value, produced by
    /// some `f`.
    pub fn get_or_init<F>(&self, f: F) -> NonZeroUsize
    where
        F: FnOnce() -> NonZeroUsize,
    {
        enum Void {}
        match self.get_or_try_init(|| Ok::<NonZeroUsize, Void>(f())) {
            Ok(val) => val,
            Err(void) => match void {},
        }
    }

    /// Gets the contents of the cell, initializing it with `f` if
    /// the cell was empty. If the cell was empty and `f` failed, an
    /// error is returned.
    ///
    /// If several threads concurrently run `get_or_init`, more than one `f` can
    /// be called. However, all threads will return the same value, produced by
    /// some `f`.
    pub fn get_or_try_init<F, E>(&self, f: F) -> Result<NonZeroUsize, E>
    where
        F: FnOnce() -> Result<NonZeroUsize, E>,
    {
        let val = self.inner.load(Ordering::Acquire);
        let res = match NonZeroUsize::new(val) {
            Some(it) => it,
            None => {
                let mut val = f()?.get();
                let exchange =
                    self.inner.compare_exchange(0, val, Ordering::AcqRel, Ordering::Acquire);
                if let Err(old) = exchange {
                    val = old;
                }
                unsafe { NonZeroUsize::new_unchecked(val) }
            }
        };
        Ok(res)
    }
}

/// A thread-safe cell which can be written to only once.
#[derive(Default, Debug)]
pub struct OnceBool {
    inner: OnceNonZeroUsize,
}

impl OnceBool {
    /// Creates a new empty cell.
    #[inline]
    pub const fn new() -> OnceBool {
        OnceBool { inner: OnceNonZeroUsize::new() }
    }

    /// Gets the underlying value.
    #[inline]
    pub fn get(&self) -> Option<bool> {
        self.inner.get().map(OnceBool::from_usize)
    }

    /// Sets the contents of this cell to `value`.
    ///
    /// Returns `Ok(())` if the cell was empty and `Err(())` if it was
    /// full.
    #[inline]
    pub fn set(&self, value: bool) -> Result<(), ()> {
        self.inner.set(OnceBool::to_usize(value))
    }

    /// Gets the contents of the cell, initializing it with `f` if the cell was
    /// empty.
    ///
    /// If several threads concurrently run `get_or_init`, more than one `f` can
    /// be called. However, all threads will return the same value, produced by
    /// some `f`.
    pub fn get_or_init<F>(&self, f: F) -> bool
    where
        F: FnOnce() -> bool,
    {
        OnceBool::from_usize(self.inner.get_or_init(|| OnceBool::to_usize(f())))
    }

    /// Gets the contents of the cell, initializing it with `f` if
    /// the cell was empty. If the cell was empty and `f` failed, an
    /// error is returned.
    ///
    /// If several threads concurrently run `get_or_init`, more than one `f` can
    /// be called. However, all threads will return the same value, produced by
    /// some `f`.
    pub fn get_or_try_init<F, E>(&self, f: F) -> Result<bool, E>
    where
        F: FnOnce() -> Result<bool, E>,
    {
        self.inner.get_or_try_init(|| f().map(OnceBool::to_usize)).map(OnceBool::from_usize)
    }

    #[inline]
    fn from_usize(value: NonZeroUsize) -> bool {
        value.get() == 1
    }

    #[inline]
    fn to_usize(value: bool) -> NonZeroUsize {
        unsafe { NonZeroUsize::new_unchecked(if value { 1 } else { 2 }) }
    }
}

/// A thread-safe cell which can be written to only once.
pub struct OnceRef<'a, T> {
    inner: AtomicPtr<T>,
    ghost: PhantomData<UnsafeCell<&'a T>>,
}

// TODO: Replace UnsafeCell with SyncUnsafeCell once stabilized
unsafe impl<'a, T: Sync> Sync for OnceRef<'a, T> {}

impl<'a, T> core::fmt::Debug for OnceRef<'a, T> {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        write!(f, "OnceRef({:?})", self.inner)
    }
}

impl<'a, T> Default for OnceRef<'a, T> {
    fn default() -> Self {
        Self::new()
    }
}

impl<'a, T> OnceRef<'a, T> {
    /// Creates a new empty cell.
    pub const fn new() -> OnceRef<'a, T> {
        OnceRef { inner: AtomicPtr::new(ptr::null_mut()), ghost: PhantomData }
    }

    /// Gets a reference to the underlying value.
    pub fn get(&self) -> Option<&'a T> {
        let ptr = self.inner.load(Ordering::Acquire);
        unsafe { ptr.as_ref() }
    }

    /// Sets the contents of this cell to `value`.
    ///
    /// Returns `Ok(())` if the cell was empty and `Err(value)` if it was
    /// full.
    pub fn set(&self, value: &'a T) -> Result<(), ()> {
        let ptr = value as *const T as *mut T;
        let exchange =
            self.inner.compare_exchange(ptr::null_mut(), ptr, Ordering::AcqRel, Ordering::Acquire);
        match exchange {
            Ok(_) => Ok(()),
            Err(_) => Err(()),
        }
    }

    /// Gets the contents of the cell, initializing it with `f` if the cell was
    /// empty.
    ///
    /// If several threads concurrently run `get_or_init`, more than one `f` can
    /// be called. However, all threads will return the same value, produced by
    /// some `f`.
    pub fn get_or_init<F>(&self, f: F) -> &'a T
    where
        F: FnOnce() -> &'a T,
    {
        enum Void {}
        match self.get_or_try_init(|| Ok::<&'a T, Void>(f())) {
            Ok(val) => val,
            Err(void) => match void {},
        }
    }

    /// Gets the contents of the cell, initializing it with `f` if
    /// the cell was empty. If the cell was empty and `f` failed, an
    /// error is returned.
    ///
    /// If several threads concurrently run `get_or_init`, more than one `f` can
    /// be called. However, all threads will return the same value, produced by
    /// some `f`.
    pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&'a T, E>
    where
        F: FnOnce() -> Result<&'a T, E>,
    {
        let mut ptr = self.inner.load(Ordering::Acquire);

        if ptr.is_null() {
            // TODO replace with `cast_mut` when MSRV reaches 1.65.0 (also in `set`)
            ptr = f()? as *const T as *mut T;
            let exchange = self.inner.compare_exchange(
                ptr::null_mut(),
                ptr,
                Ordering::AcqRel,
                Ordering::Acquire,
            );
            if let Err(old) = exchange {
                ptr = old;
            }
        }

        Ok(unsafe { &*ptr })
    }

    /// ```compile_fail
    /// use once_cell::race::OnceRef;
    ///
    /// let mut l = OnceRef::new();
    ///
    /// {
    ///     let y = 2;
    ///     let mut r = OnceRef::new();
    ///     r.set(&y).unwrap();
    ///     core::mem::swap(&mut l, &mut r);
    /// }
    ///
    /// // l now contains a dangling reference to y
    /// eprintln!("uaf: {}", l.get().unwrap());
    /// ```
    fn _dummy() {}
}

#[cfg(feature = "alloc")]
pub use self::once_box::OnceBox;

#[cfg(feature = "alloc")]
mod once_box {
    use super::atomic::{AtomicPtr, Ordering};
    use core::{marker::PhantomData, ptr};

    use alloc::boxed::Box;

    /// A thread-safe cell which can be written to only once.
    pub struct OnceBox<T> {
        inner: AtomicPtr<T>,
        ghost: PhantomData<Option<Box<T>>>,
    }

    impl<T> core::fmt::Debug for OnceBox<T> {
        fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
            write!(f, "OnceBox({:?})", self.inner.load(Ordering::Relaxed))
        }
    }

    impl<T> Default for OnceBox<T> {
        fn default() -> Self {
            Self::new()
        }
    }

    impl<T> Drop for OnceBox<T> {
        fn drop(&mut self) {
            let ptr = *self.inner.get_mut();
            if !ptr.is_null() {
                drop(unsafe { Box::from_raw(ptr) })
            }
        }
    }

    impl<T> OnceBox<T> {
        /// Creates a new empty cell.
        pub const fn new() -> OnceBox<T> {
            OnceBox { inner: AtomicPtr::new(ptr::null_mut()), ghost: PhantomData }
        }

        /// Gets a reference to the underlying value.
        pub fn get(&self) -> Option<&T> {
            let ptr = self.inner.load(Ordering::Acquire);
            if ptr.is_null() {
                return None;
            }
            Some(unsafe { &*ptr })
        }

        /// Sets the contents of this cell to `value`.
        ///
        /// Returns `Ok(())` if the cell was empty and `Err(value)` if it was
        /// full.
        pub fn set(&self, value: Box<T>) -> Result<(), Box<T>> {
            let ptr = Box::into_raw(value);
            let exchange = self.inner.compare_exchange(
                ptr::null_mut(),
                ptr,
                Ordering::AcqRel,
                Ordering::Acquire,
            );
            if exchange.is_err() {
                let value = unsafe { Box::from_raw(ptr) };
                return Err(value);
            }
            Ok(())
        }

        /// Gets the contents of the cell, initializing it with `f` if the cell was
        /// empty.
        ///
        /// If several threads concurrently run `get_or_init`, more than one `f` can
        /// be called. However, all threads will return the same value, produced by
        /// some `f`.
        pub fn get_or_init<F>(&self, f: F) -> &T
        where
            F: FnOnce() -> Box<T>,
        {
            enum Void {}
            match self.get_or_try_init(|| Ok::<Box<T>, Void>(f())) {
                Ok(val) => val,
                Err(void) => match void {},
            }
        }

        /// Gets the contents of the cell, initializing it with `f` if
        /// the cell was empty. If the cell was empty and `f` failed, an
        /// error is returned.
        ///
        /// If several threads concurrently run `get_or_init`, more than one `f` can
        /// be called. However, all threads will return the same value, produced by
        /// some `f`.
        pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E>
        where
            F: FnOnce() -> Result<Box<T>, E>,
        {
            let mut ptr = self.inner.load(Ordering::Acquire);

            if ptr.is_null() {
                let val = f()?;
                ptr = Box::into_raw(val);
                let exchange = self.inner.compare_exchange(
                    ptr::null_mut(),
                    ptr,
                    Ordering::AcqRel,
                    Ordering::Acquire,
                );
                if let Err(old) = exchange {
                    drop(unsafe { Box::from_raw(ptr) });
                    ptr = old;
                }
            };
            Ok(unsafe { &*ptr })
        }
    }

    unsafe impl<T: Sync + Send> Sync for OnceBox<T> {}

    /// ```compile_fail
    /// struct S(*mut ());
    /// unsafe impl Sync for S {}
    ///
    /// fn share<T: Sync>(_: &T) {}
    /// share(&once_cell::race::OnceBox::<S>::new());
    /// ```
    fn _dummy() {}
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/thiserror-1.0.61/src/display.rs

Source (jump to first uncovered line)
use core::fmt::Display;
use std::path::{self, Path, PathBuf};

#[doc(hidden)]
pub trait AsDisplay<'a> {
    // TODO: convert to generic associated type.
    // https://github.com/dtolnay/thiserror/pull/253
    type Target: Display;

    fn as_display(&'a self) -> Self::Target;
}

impl<'a, T> AsDisplay<'a> for &T
where
    T: Display + 'a,
{
    type Target = &'a T;

    fn as_display(&'a self) -> Self::Target {
        *self
    }
}

impl<'a> AsDisplay<'a> for Path {
    type Target = path::Display<'a>;

    #[inline]
    fn as_display(&'a self) -> Self::Target {
        self.display()
    }
}

impl<'a> AsDisplay<'a> for PathBuf {
    type Target = path::Display<'a>;

    #[inline]
    fn as_display(&'a self) -> Self::Target {
        self.display()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component.rs

Source (jump to first uncovered line)
mod aliases;
mod builder;
mod canonicals;
mod components;
mod exports;
mod imports;
mod instances;
mod modules;
mod names;
mod start;
mod types;

pub use self::aliases::*;
pub use self::builder::*;
pub use self::canonicals::*;
pub use self::components::*;
pub use self::exports::*;
pub use self::imports::*;
pub use self::instances::*;
pub use self::modules::*;
pub use self::names::*;
pub use self::start::*;
pub use self::types::*;

use crate::{CustomSection, Encode, ProducersSection, RawCustomSection};

// Core sorts extended by the component model
const CORE_TYPE_SORT: u8 = 0x10;
const CORE_MODULE_SORT: u8 = 0x11;
const CORE_INSTANCE_SORT: u8 = 0x12;

const CORE_SORT: u8 = 0x00;
const FUNCTION_SORT: u8 = 0x01;
const VALUE_SORT: u8 = 0x02;
const TYPE_SORT: u8 = 0x03;
const COMPONENT_SORT: u8 = 0x04;
const INSTANCE_SORT: u8 = 0x05;

/// A WebAssembly component section.
///
/// Various builders defined in this crate already implement this trait, but you
/// can also implement it yourself for your own custom section builders, or use
/// `RawSection` to use a bunch of raw bytes as a section.
pub trait ComponentSection: Encode {
    /// Gets the section identifier for this section.
    fn id(&self) -> u8;

    /// Appends this section to the specified destination list of bytes.
    fn append_to_component(&self, dst: &mut Vec<u8>) {
        dst.push(self.id());
        self.encode(dst);
    }
}

/// Known section identifiers of WebAssembly components.
///
/// These sections are supported by the component model proposal.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd)]
#[repr(u8)]
pub enum ComponentSectionId {
    /// The section is a core custom section.
    CoreCustom = 0,
    /// The section is a core module section.
    CoreModule = 1,
    /// The section is a core instance section.
    CoreInstance = 2,
    /// The section is a core type section.
    CoreType = 3,
    /// The section is a component section.
    Component = 4,
    /// The section is an instance section.
    Instance = 5,
    /// The section is an alias section.
    Alias = 6,
    /// The section is a type section.
    Type = 7,
    /// The section is a canonical function section.
    CanonicalFunction = 8,
    /// The section is a start section.
    Start = 9,
    /// The section is an import section.
    Import = 10,
    /// The section is an export section.
    Export = 11,
}

impl From<ComponentSectionId> for u8 {
    #[inline]
    fn from(id: ComponentSectionId) -> u8 {
        id as u8
    }
}

impl Encode for ComponentSectionId {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.push(*self as u8);
    }
}

/// Represents a WebAssembly component that is being encoded.
///
/// Unlike core WebAssembly modules, the sections of a component
/// may appear in any order and may be repeated.
///
/// Components may also added as a section to other components.
#[derive(Clone, Debug)]
pub struct Component {
    bytes: Vec<u8>,
}

impl Component {
    /// The 8-byte header at the beginning of all components.
    #[rustfmt::skip]
    pub const HEADER: [u8; 8] = [
        // Magic
        0x00, 0x61, 0x73, 0x6D,
        // Version
        0x0d, 0x00, 0x01, 0x00,
    ];

    /// Begin writing a new `Component`.
    pub fn new() -> Self {
        Self {
            bytes: Self::HEADER.to_vec(),
        }
    }

    /// Finish writing this component and extract ownership of the encoded bytes.
    pub fn finish(self) -> Vec<u8> {
        self.bytes
    }

    /// Write a section to this component.
    pub fn section(&mut self, section: &impl ComponentSection) -> &mut Self {
        self.bytes.push(section.id());
        section.encode(&mut self.bytes);
        self
    }

    /// View the encoded bytes.
    pub fn as_slice(&self) -> &[u8] {
        &self.bytes
    }
}

impl Default for Component {
    fn default() -> Self {
        Self::new()
    }
}

impl ComponentSection for CustomSection<'_> {
    fn id(&self) -> u8 {
        ComponentSectionId::CoreCustom.into()
    }
}

impl ComponentSection for RawCustomSection<'_> {
    fn id(&self) -> u8 {
        ComponentSectionId::CoreCustom.into()
    }
}

impl ComponentSection for ProducersSection {
    fn id(&self) -> u8 {
        ComponentSectionId::CoreCustom.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/aliases.rs

Source (jump to first uncovered line)
use super::{COMPONENT_SORT, CORE_MODULE_SORT, CORE_SORT, CORE_TYPE_SORT, TYPE_SORT};
use crate::{
    encode_section, ComponentExportKind, ComponentSection, ComponentSectionId, Encode, ExportKind,
};

/// Represents the kinds of outer aliasable items in a component.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum ComponentOuterAliasKind {
    /// The alias is to a core module.
    CoreModule,
    /// The alias is to a core type.
    CoreType,
    /// The alias is to a type.
    Type,
    /// The alias is to a component.
    Component,
}

impl Encode for ComponentOuterAliasKind {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            Self::CoreModule => {
                sink.push(CORE_SORT);
                sink.push(CORE_MODULE_SORT);
            }
            Self::CoreType => {
                sink.push(CORE_SORT);
                sink.push(CORE_TYPE_SORT);
            }
            Self::Type => sink.push(TYPE_SORT),
            Self::Component => sink.push(COMPONENT_SORT),
        }
    }
}

/// An encoder for the alias section of WebAssembly component.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, Alias, ComponentAliasSection, ComponentExportKind, ComponentOuterAliasKind};
///
/// let mut aliases = ComponentAliasSection::new();
/// aliases.alias(Alias::InstanceExport { instance: 0, kind: ComponentExportKind::Func, name: "f" });
/// aliases.alias(Alias::Outer { count: 0, kind: ComponentOuterAliasKind::Type, index: 1 });
///
/// let mut component = Component::new();
/// component.section(&aliases);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct ComponentAliasSection {
    bytes: Vec<u8>,
    num_added: u32,
}

/// Different forms of aliases that can be inserted into a
/// [`ComponentAliasSection`].
#[derive(Copy, Clone, Debug)]
pub enum Alias<'a> {
    /// An alias of a component instance export.
    InstanceExport {
        /// The index of the component instance that's being aliased from.
        instance: u32,
        /// The kind of item that's being extracted from the component
        /// instance.
        kind: ComponentExportKind,
        /// The name of the export that's being aliased.
        name: &'a str,
    },
    /// Same as `InstanceExport`, but for core instances.
    #[allow(missing_docs)]
    CoreInstanceExport {
        instance: u32,
        kind: ExportKind,
        name: &'a str,
    },
    /// Aliasing an item from an outer component.
    Outer {
        /// The kind of item being aliased, either a type or a component.
        kind: ComponentOuterAliasKind,
        /// Number of levels "up" to go to lookup the index within. Level 0 is
        /// the current scope and level 1 is the enclosing scope, and so on.
        count: u32,
        /// The index of the item to alias within the scope referenced by
        /// `count`.
        index: u32,
    },
}

impl ComponentAliasSection {
    /// Create a new alias section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of aliases in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define an alias to a component instance's export.
    pub fn alias(&mut self, alias: Alias<'_>) -> &mut Self {
        alias.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for ComponentAliasSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl ComponentSection for ComponentAliasSection {
    fn id(&self) -> u8 {
        ComponentSectionId::Alias.into()
    }
}

impl Encode for Alias<'_> {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            Alias::InstanceExport {
                instance,
                kind,
                name,
            } => {
                kind.encode(sink);
                sink.push(0x00);
                instance.encode(sink);
                name.encode(sink);
            }
            Alias::CoreInstanceExport {
                instance,
                kind,
                name,
            } => {
                sink.push(CORE_SORT);
                kind.encode(sink);
                sink.push(0x01);
                instance.encode(sink);
                name.encode(sink);
            }
            Alias::Outer { kind, count, index } => {
                kind.encode(sink);
                sink.push(0x02);
                count.encode(sink);
                index.encode(sink);
            }
        }
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/builder.rs

Source (jump to first uncovered line)
use crate::component::*;
use crate::{ExportKind, Module, RawSection, ValType};
use std::mem;

/// Convenience type to build a component incrementally and automatically keep
/// track of index spaces.
///
/// This type is intended to be a wrapper around the [`Component`] encoding type
/// which is useful for building it up incrementally over time. This type will
/// automatically collect definitions into sections and reports the index of all
/// items added by keeping track of indices internally.
#[derive(Debug, Default)]
pub struct ComponentBuilder {
    /// The binary component that's being built.
    component: Component,

    /// The last section which was appended to during encoding. This type is
    /// generated by the `section_accessors` macro below.
    ///
    /// When something is encoded this is used if it matches the kind of item
    /// being encoded, otherwise it's "flushed" to the output component and a
    /// new section is started.
    last_section: LastSection,

    // Core index spaces
    core_modules: u32,
    core_funcs: u32,
    core_types: u32,
    core_memories: u32,
    core_tables: u32,
    core_instances: u32,
    core_tags: u32,
    core_globals: u32,

    // Component index spaces
    funcs: u32,
    instances: u32,
    types: u32,
    components: u32,
    values: u32,
}

impl ComponentBuilder {
    /// Returns the current number of core modules.
    pub fn core_module_count(&self) -> u32 {
        self.core_modules
    }

    /// Returns the current number of core funcs.
    pub fn core_func_count(&self) -> u32 {
        self.core_funcs
    }

    /// Returns the current number of core types.
    pub fn core_type_count(&self) -> u32 {
        self.core_types
    }

    /// Returns the current number of core memories.
    pub fn core_memory_count(&self) -> u32 {
        self.core_memories
    }

    /// Returns the current number of core tables.
    pub fn core_table_count(&self) -> u32 {
        self.core_tables
    }

    /// Returns the current number of core instances.
    pub fn core_instance_count(&self) -> u32 {
        self.core_instances
    }

    /// Returns the current number of core tags.
    pub fn core_tag_count(&self) -> u32 {
        self.core_tags
    }

    /// Returns the current number of core globals.
    pub fn core_global_count(&self) -> u32 {
        self.core_globals
    }

    /// Returns the current number of component funcs.
    pub fn func_count(&self) -> u32 {
        self.funcs
    }

    /// Returns the current number of component instances.
    pub fn instance_count(&self) -> u32 {
        self.instances
    }

    /// Returns the current number of component values.
    pub fn value_count(&self) -> u32 {
        self.values
    }

    /// Returns the current number of components.
    pub fn component_count(&self) -> u32 {
        self.components
    }

    /// Returns the current number of component types.
    pub fn type_count(&self) -> u32 {
        self.types
    }

    /// Completes this component and returns the binary encoding of the entire
    /// component.
    pub fn finish(mut self) -> Vec<u8> {
        self.flush();
        self.component.finish()
    }

    /// Encodes a core wasm `Module` into this component, returning its index.
    pub fn core_module(&mut self, module: &Module) -> u32 {
        self.flush();
        self.component.section(&ModuleSection(module));
        inc(&mut self.core_modules)
    }

    /// Encodes a core wasm `module` into this component, returning its index.
    pub fn core_module_raw(&mut self, module: &[u8]) -> u32 {
        self.flush();
        self.component.section(&RawSection {
            id: ComponentSectionId::CoreModule.into(),
            data: module,
        });
        inc(&mut self.core_modules)
    }

    /// Instantiates a core wasm module at `module_index` with the `args`
    /// provided.
    ///
    /// Returns the index of the core wasm instance crated.
    pub fn core_instantiate<'a, A>(&mut self, module_index: u32, args: A) -> u32
    where
        A: IntoIterator<Item = (&'a str, ModuleArg)>,
        A::IntoIter: ExactSizeIterator,
    {
        self.instances().instantiate(module_index, args);
        inc(&mut self.core_instances)
    }

    /// Creates a new core wasm instance from the `exports` provided.
    ///
    /// Returns the index of the core wasm instance crated.
    pub fn core_instantiate_exports<'a, E>(&mut self, exports: E) -> u32
    where
        E: IntoIterator<Item = (&'a str, ExportKind, u32)>,
        E::IntoIter: ExactSizeIterator,
    {
        self.instances().export_items(exports);
        inc(&mut self.core_instances)
    }

    /// Creates a new aliased item where the core `instance` specified has its
    /// export `name` aliased out with the `kind` specified.
    ///
    /// Returns the index of the item crated.
    pub fn core_alias_export(&mut self, instance: u32, name: &str, kind: ExportKind) -> u32 {
        self.alias(Alias::CoreInstanceExport {
            instance,
            kind,
            name,
        })
    }

    /// Adds a new alias to this component
    pub fn alias(&mut self, alias: Alias<'_>) -> u32 {
        self.aliases().alias(alias);
        match alias {
            Alias::InstanceExport { kind, .. } => self.inc_kind(kind),
            Alias::CoreInstanceExport { kind, .. } => self.inc_core_kind(kind),
            Alias::Outer {
                kind: ComponentOuterAliasKind::Type,
                ..
            } => inc(&mut self.types),
            Alias::Outer {
                kind: ComponentOuterAliasKind::CoreModule,
                ..
            } => inc(&mut self.core_modules),
            Alias::Outer {
                kind: ComponentOuterAliasKind::Component,
                ..
            } => inc(&mut self.components),
            Alias::Outer {
                kind: ComponentOuterAliasKind::CoreType,
                ..
            } => inc(&mut self.core_types),
        }
    }

    /// Creates an alias to a previous component instance's exported item.
    ///
    /// The `instance` provided is the instance to access and the `name` is the
    /// item to access.
    ///
    /// Returns the index of the new item defined.
    pub fn alias_export(&mut self, instance: u32, name: &str, kind: ComponentExportKind) -> u32 {
        self.alias(Alias::InstanceExport {
            instance,
            kind,
            name,
        })
    }

    fn inc_kind(&mut self, kind: ComponentExportKind) -> u32 {
        match kind {
            ComponentExportKind::Func => inc(&mut self.funcs),
            ComponentExportKind::Module => inc(&mut self.core_modules),
            ComponentExportKind::Type => inc(&mut self.types),
            ComponentExportKind::Component => inc(&mut self.components),
            ComponentExportKind::Instance => inc(&mut self.instances),
            ComponentExportKind::Value => inc(&mut self.values),
        }
    }

    fn inc_core_kind(&mut self, kind: ExportKind) -> u32 {
        match kind {
            ExportKind::Func => inc(&mut self.core_funcs),
            ExportKind::Table => inc(&mut self.core_tables),
            ExportKind::Memory => inc(&mut self.core_memories),
            ExportKind::Global => inc(&mut self.core_globals),
            ExportKind::Tag => inc(&mut self.core_tags),
        }
    }

    /// Lowers the `func_index` component function into a core wasm function
    /// using the `options` provided.
    ///
    /// Returns the index of the core wasm function created.
    pub fn lower_func<O>(&mut self, func_index: u32, options: O) -> u32
    where
        O: IntoIterator<Item = CanonicalOption>,
        O::IntoIter: ExactSizeIterator,
    {
        self.canonical_functions().lower(func_index, options);
        inc(&mut self.core_funcs)
    }

    /// Lifts the core wasm `core_func_index` function with the component
    /// function type `type_index` and `options`.
    ///
    /// Returns the index of the component function created.
    pub fn lift_func<O>(&mut self, core_func_index: u32, type_index: u32, options: O) -> u32
    where
        O: IntoIterator<Item = CanonicalOption>,
        O::IntoIter: ExactSizeIterator,
    {
        self.canonical_functions()
            .lift(core_func_index, type_index, options);
        inc(&mut self.funcs)
    }

    /// Imports a new item into this component with the `name` and `ty` specified.
    pub fn import(&mut self, name: &str, ty: ComponentTypeRef) -> u32 {
        let ret = match &ty {
            ComponentTypeRef::Instance(_) => inc(&mut self.instances),
            ComponentTypeRef::Func(_) => inc(&mut self.funcs),
            ComponentTypeRef::Type(..) => inc(&mut self.types),
            ComponentTypeRef::Component(_) => inc(&mut self.components),
            ComponentTypeRef::Module(_) => inc(&mut self.core_modules),
            ComponentTypeRef::Value(_) => inc(&mut self.values),
        };
        self.imports().import(name, ty);
        ret
    }

    /// Exports a new item from this component with the `name` and `kind`
    /// specified.
    ///
    /// The `idx` is the item to export and the `ty` is an optional type to
    /// ascribe to the export.
    pub fn export(
        &mut self,
        name: &str,
        kind: ComponentExportKind,
        idx: u32,
        ty: Option<ComponentTypeRef>,
    ) -> u32 {
        self.exports().export(name, kind, idx, ty);
        self.inc_kind(kind)
    }

    /// Creates a new encoder for the next core type in this component.
    pub fn core_type(&mut self) -> (u32, CoreTypeEncoder<'_>) {
        (inc(&mut self.core_types), self.core_types().ty())
    }

    /// Creates a new encoder for the next type in this component.
    pub fn ty(&mut self) -> (u32, ComponentTypeEncoder<'_>) {
        (inc(&mut self.types), self.types().ty())
    }

    /// Creates a new instance type within this component.
    pub fn type_instance(&mut self, ty: &InstanceType) -> u32 {
        self.types().instance(ty);
        inc(&mut self.types)
    }

    /// Creates a new component type within this component.
    pub fn type_component(&mut self, ty: &ComponentType) -> u32 {
        self.types().component(ty);
        inc(&mut self.types)
    }

    /// Creates a new defined component type within this component.
    pub fn type_defined(&mut self) -> (u32, ComponentDefinedTypeEncoder<'_>) {
        (inc(&mut self.types), self.types().defined_type())
    }

    /// Creates a new component function type within this component.
    pub fn type_function(&mut self) -> (u32, ComponentFuncTypeEncoder<'_>) {
        (inc(&mut self.types), self.types().function())
    }

    /// Declares a
    pub fn type_resource(&mut self, rep: ValType, dtor: Option<u32>) -> u32 {
        self.types().resource(rep, dtor);
        inc(&mut self.types)
    }

    /// Defines a new subcomponent of this component.
    pub fn component(&mut self, mut builder: ComponentBuilder) -> u32 {
        builder.flush();
        self.flush();
        self.component
            .section(&NestedComponentSection(&builder.component));
        inc(&mut self.components)
    }

    /// Defines a new subcomponent of this component.
    pub fn component_raw(&mut self, data: &[u8]) -> u32 {
        let raw_section = RawSection {
            id: ComponentSectionId::Component.into(),
            data,
        };
        self.flush();
        self.component.section(&raw_section);
        inc(&mut self.components)
    }

    /// Instantiates the `component_index` specified with the `args` specified.
    pub fn instantiate<A, S>(&mut self, component_index: u32, args: A) -> u32
    where
        A: IntoIterator<Item = (S, ComponentExportKind, u32)>,
        A::IntoIter: ExactSizeIterator,
        S: AsRef<str>,
    {
        self.component_instances()
            .instantiate(component_index, args);
        inc(&mut self.instances)
    }

    /// Declares a new `resource.drop` intrinsic.
    pub fn resource_drop(&mut self, ty: u32) -> u32 {
        self.canonical_functions().resource_drop(ty);
        inc(&mut self.core_funcs)
    }

    /// Declares a new `resource.new` intrinsic.
    pub fn resource_new(&mut self, ty: u32) -> u32 {
        self.canonical_functions().resource_new(ty);
        inc(&mut self.core_funcs)
    }

    /// Declares a new `resource.rep` intrinsic.
    pub fn resource_rep(&mut self, ty: u32) -> u32 {
        self.canonical_functions().resource_rep(ty);
        inc(&mut self.core_funcs)
    }

    /// Adds a new custom section to this component.
    pub fn custom_section(&mut self, section: &CustomSection<'_>) {
        self.flush();
        self.component.section(section);
    }

    /// Adds a new custom section to this component.
    pub fn raw_custom_section(&mut self, section: &[u8]) {
        self.flush();
        self.component.section(&RawCustomSection(section));
    }
}

// Helper macro to generate methods on `ComponentBuilder` to get specific
// section encoders that automatically flush and write out prior sections as
// necessary.
macro_rules! section_accessors {
    ($($method:ident => $section:ident)*) => (
        #[derive(Debug, Default)]
        enum LastSection {
            #[default]
            None,
            $($section($section),)*
        }

        impl ComponentBuilder {
            $(
                fn $method(&mut self) -> &mut $section {
                    match &self.last_section {
                        // The last encoded section matches the section that's
                        // being requested, so no change is necessary.
                        LastSection::$section(_) => {}

                        // Otherwise the last section didn't match this section,
                        // so flush any prior section if needed and start
                        // encoding the desired section of this method.
                        _ => {
                            self.flush();
                            self.last_section = LastSection::$section($section::new());
                        }
                    }
                    match &mut self.last_section {
                        LastSection::$section(ret) => ret,
                        _ => unreachable!()
                    }
                }
            )*

            /// Writes out the last section into the final component binary if
            /// there is a section specified, otherwise does nothing.
            fn flush(&mut self) {
                match mem::take(&mut self.last_section) {
                    LastSection::None => {}
                    $(
                        LastSection::$section(section) => {
                            self.component.section(&section);
                        }
                    )*
                }
            }

        }
    )
}

section_accessors! {
    component_instances => ComponentInstanceSection
    instances => InstanceSection
    canonical_functions => CanonicalFunctionSection
    aliases => ComponentAliasSection
    exports => ComponentExportSection
    imports => ComponentImportSection
    types => ComponentTypeSection
    core_types => CoreTypeSection
}

fn inc(idx: &mut u32) -> u32 {
    let ret = *idx;
    *idx += 1;
    ret
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/canonicals.rs

Source (jump to first uncovered line)
use crate::{encode_section, ComponentSection, ComponentSectionId, Encode};

/// Represents options for canonical function definitions.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum CanonicalOption {
    /// The string types in the function signature are UTF-8 encoded.
    UTF8,
    /// The string types in the function signature are UTF-16 encoded.
    UTF16,
    /// The string types in the function signature are compact UTF-16 encoded.
    CompactUTF16,
    /// The memory to use if the lifting or lowering of a function requires memory access.
    ///
    /// The value is an index to a core memory.
    Memory(u32),
    /// The realloc function to use if the lifting or lowering of a function requires memory
    /// allocation.
    ///
    /// The value is an index to a core function of type `(func (param i32 i32 i32 i32) (result i32))`.
    Realloc(u32),
    /// The post-return function to use if the lifting of a function requires
    /// cleanup after the function returns.
    PostReturn(u32),
}

impl Encode for CanonicalOption {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            Self::UTF8 => sink.push(0x00),
            Self::UTF16 => sink.push(0x01),
            Self::CompactUTF16 => sink.push(0x02),
            Self::Memory(idx) => {
                sink.push(0x03);
                idx.encode(sink);
            }
            Self::Realloc(idx) => {
                sink.push(0x04);
                idx.encode(sink);
            }
            Self::PostReturn(idx) => {
                sink.push(0x05);
                idx.encode(sink);
            }
        }
    }
}

/// An encoder for the canonical function section of WebAssembly components.
///
/// # Example
///
/// ```
/// use wasm_encoder::{Component, CanonicalFunctionSection, CanonicalOption};
///
/// let mut functions = CanonicalFunctionSection::new();
/// functions.lift(0, 0, [CanonicalOption::UTF8]);
///
/// let mut component = Component::new();
/// component.section(&functions);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct CanonicalFunctionSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl CanonicalFunctionSection {
    /// Construct a new component function section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of functions in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define a function that will lift a core WebAssembly function to the canonical ABI.
    pub fn lift<O>(&mut self, core_func_index: u32, type_index: u32, options: O) -> &mut Self
    where
        O: IntoIterator<Item = CanonicalOption>,
        O::IntoIter: ExactSizeIterator,
    {
        let options = options.into_iter();
        self.bytes.push(0x00);
        self.bytes.push(0x00);
        core_func_index.encode(&mut self.bytes);
        options.len().encode(&mut self.bytes);
        for option in options {
            option.encode(&mut self.bytes);
        }
        type_index.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// Define a function that will lower a canonical ABI function to a core WebAssembly function.
    pub fn lower<O>(&mut self, func_index: u32, options: O) -> &mut Self
    where
        O: IntoIterator<Item = CanonicalOption>,
        O::IntoIter: ExactSizeIterator,
    {
        let options = options.into_iter();
        self.bytes.push(0x01);
        self.bytes.push(0x00);
        func_index.encode(&mut self.bytes);
        options.len().encode(&mut self.bytes);
        for option in options {
            option.encode(&mut self.bytes);
        }
        self.num_added += 1;
        self
    }

    /// Defines a function which will create an owned handle to the resource
    /// specified by `ty_index`.
    pub fn resource_new(&mut self, ty_index: u32) -> &mut Self {
        self.bytes.push(0x02);
        ty_index.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// Defines a function which will drop the specified type of handle.
    pub fn resource_drop(&mut self, ty_index: u32) -> &mut Self {
        self.bytes.push(0x03);
        ty_index.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// Defines a function which will return the representation of the specified
    /// resource type.
    pub fn resource_rep(&mut self, ty_index: u32) -> &mut Self {
        self.bytes.push(0x04);
        ty_index.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for CanonicalFunctionSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl ComponentSection for CanonicalFunctionSection {
    fn id(&self) -> u8 {
        ComponentSectionId::CanonicalFunction.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/components.rs

Source (jump to first uncovered line)
use crate::{Component, ComponentSection, ComponentSectionId, Encode};

/// An encoder for the component section of WebAssembly components.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, NestedComponentSection};
///
/// let mut nested = Component::new();
/// let mut component = Component::new();
/// component.section(&NestedComponentSection(&nested));
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug)]
pub struct NestedComponentSection<'a>(pub &'a Component);

impl Encode for NestedComponentSection<'_> {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.0.bytes.encode(sink);
    }
}

impl ComponentSection for NestedComponentSection<'_> {
    fn id(&self) -> u8 {
        ComponentSectionId::Component.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/exports.rs

Source (jump to first uncovered line)
use super::{
    COMPONENT_SORT, CORE_MODULE_SORT, CORE_SORT, FUNCTION_SORT, INSTANCE_SORT, TYPE_SORT,
    VALUE_SORT,
};
use crate::{encode_section, ComponentSection, ComponentSectionId, ComponentTypeRef, Encode};

/// Represents the kind of an export from a WebAssembly component.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum ComponentExportKind {
    /// The export is a core module.
    Module,
    /// The export is a function.
    Func,
    /// The export is a value.
    Value,
    /// The export is a type.
    Type,
    /// The export is an instance.
    Instance,
    /// The export is a component.
    Component,
}

impl Encode for ComponentExportKind {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            Self::Module => {
                sink.push(CORE_SORT);
                sink.push(CORE_MODULE_SORT);
            }
            Self::Func => {
                sink.push(FUNCTION_SORT);
            }
            Self::Value => {
                sink.push(VALUE_SORT);
            }
            Self::Type => {
                sink.push(TYPE_SORT);
            }
            Self::Instance => {
                sink.push(INSTANCE_SORT);
            }
            Self::Component => {
                sink.push(COMPONENT_SORT);
            }
        }
    }
}

/// An encoder for the export section of WebAssembly component.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, ComponentExportSection, ComponentExportKind};
///
/// // This exports a function named "foo"
/// let mut exports = ComponentExportSection::new();
/// exports.export("foo", ComponentExportKind::Func, 0, None);
///
/// let mut component = Component::new();
/// component.section(&exports);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct ComponentExportSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl ComponentExportSection {
    /// Create a new component export section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of exports in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define an export in the export section.
    pub fn export(
        &mut self,
        name: &str,
        kind: ComponentExportKind,
        index: u32,
        ty: Option<ComponentTypeRef>,
    ) -> &mut Self {
        crate::component::imports::push_extern_name_byte(&mut self.bytes, name);
        name.encode(&mut self.bytes);
        kind.encode(&mut self.bytes);
        index.encode(&mut self.bytes);
        match ty {
            Some(ty) => {
                self.bytes.push(0x01);
                ty.encode(&mut self.bytes);
            }
            None => {
                self.bytes.push(0x00);
            }
        }
        self.num_added += 1;
        self
    }
}

impl Encode for ComponentExportSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl ComponentSection for ComponentExportSection {
    fn id(&self) -> u8 {
        ComponentSectionId::Export.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/imports.rs

Source (jump to first uncovered line)
use crate::{
    encode_section, ComponentExportKind, ComponentSection, ComponentSectionId, ComponentValType,
    Encode,
};

/// Represents the possible type bounds for type references.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
pub enum TypeBounds {
    /// The type is bounded by equality to the type index specified.
    Eq(u32),
    /// This type is a fresh resource type,
    SubResource,
}

impl Encode for TypeBounds {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            Self::Eq(i) => {
                sink.push(0x00);
                i.encode(sink);
            }
            Self::SubResource => sink.push(0x01),
        }
    }
}

/// Represents a reference to a type.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
pub enum ComponentTypeRef {
    /// The reference is to a core module type.
    ///
    /// The index is expected to be core type index to a core module type.
    Module(u32),
    /// The reference is to a function type.
    ///
    /// The index is expected to be a type index to a function type.
    Func(u32),
    /// The reference is to a value type.
    Value(ComponentValType),
    /// The reference is to a bounded type.
    Type(TypeBounds),
    /// The reference is to an instance type.
    ///
    /// The index is expected to be a type index to an instance type.
    Instance(u32),
    /// The reference is to a component type.
    ///
    /// The index is expected to be a type index to a component type.
    Component(u32),
}

impl ComponentTypeRef {
    /// Gets the export kind of the reference.
    pub fn kind(&self) -> ComponentExportKind {
        match self {
            Self::Module(_) => ComponentExportKind::Module,
            Self::Func(_) => ComponentExportKind::Func,
            Self::Value(_) => ComponentExportKind::Value,
            Self::Type(..) => ComponentExportKind::Type,
            Self::Instance(_) => ComponentExportKind::Instance,
            Self::Component(_) => ComponentExportKind::Component,
        }
    }
}

impl Encode for ComponentTypeRef {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.kind().encode(sink);

        match self {
            Self::Module(idx) | Self::Func(idx) | Self::Instance(idx) | Self::Component(idx) => {
                idx.encode(sink);
            }
            Self::Value(ty) => ty.encode(sink),
            Self::Type(bounds) => bounds.encode(sink),
        }
    }
}

/// An encoder for the import section of WebAssembly components.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, ComponentTypeSection, PrimitiveValType, ComponentImportSection, ComponentTypeRef};
///
/// let mut types = ComponentTypeSection::new();
///
/// // Define a function type of `[string, string] -> string`.
/// types
///   .function()
///   .params(
///     [
///       ("a", PrimitiveValType::String),
///       ("b", PrimitiveValType::String)
///     ]
///   )
///   .result(PrimitiveValType::String);
///
/// // This imports a function named `f` with the type defined above
/// let mut imports = ComponentImportSection::new();
/// imports.import("f", ComponentTypeRef::Func(0));
///
/// let mut component = Component::new();
/// component.section(&types);
/// component.section(&imports);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct ComponentImportSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl ComponentImportSection {
    /// Create a new component import section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of imports in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define an import in the component import section.
    pub fn import(&mut self, name: &str, ty: ComponentTypeRef) -> &mut Self {
        push_extern_name_byte(&mut self.bytes, name);
        name.encode(&mut self.bytes);
        ty.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for ComponentImportSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl ComponentSection for ComponentImportSection {
    fn id(&self) -> u8 {
        ComponentSectionId::Import.into()
    }
}

/// Prior to WebAssembly/component-model#263 import and export names were
/// discriminated with a leading byte indicating what kind of import they are.
/// After that PR though names are always prefixed with a 0x00 byte.
///
/// This function is a compatibility shim for the time being while this change
/// is being rolled out. That PR is technically a spec-breaking change relative
/// to prior but we want old tooling to continue to work with new modules. To
/// handle that names that look like IDs, `a:b/c`, get an 0x01 prefix instead of
/// the spec-defined 0x00 prefix. That makes components produced by current
/// versions of this crate compatible with older parsers.
///
/// Note that wasmparser has a similar case where it parses either 0x01 or 0x00.
/// That means that the selection of a byte here doesn't actually matter for
/// wasmparser's own validation. Eventually this will go away and an 0x00 byte
/// will always be emitted to align with the spec.
pub(crate) fn push_extern_name_byte(bytes: &mut Vec<u8>, name: &str) {
    if name.contains(':') {
        bytes.push(0x01);
    } else {
        bytes.push(0x00);
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/instances.rs

Source (jump to first uncovered line)
use super::CORE_INSTANCE_SORT;
use crate::{
    encode_section, ComponentExportKind, ComponentSection, ComponentSectionId, Encode, ExportKind,
};

/// Represents an argument to a module instantiation.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum ModuleArg {
    /// The argument is an instance.
    Instance(u32),
}

impl Encode for ModuleArg {
    fn encode(&self, sink: &mut Vec<u8>) {
        let (sort, idx) = match self {
            Self::Instance(idx) => (CORE_INSTANCE_SORT, *idx),
        };
        sink.push(sort);
        idx.encode(sink);
    }
}

/// An encoder for the core instance section of WebAssembly components.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, InstanceSection, ExportKind, ModuleArg};
///
/// let mut instances = InstanceSection::new();
/// instances.export_items([("foo", ExportKind::Func, 0)]);
/// instances.instantiate(1, [("foo", ModuleArg::Instance(0))]);
///
/// let mut component = Component::new();
/// component.section(&instances);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct InstanceSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl InstanceSection {
    /// Create a new core instance section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of instances in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define an instance by instantiating a core module.
    pub fn instantiate<A, S>(&mut self, module_index: u32, args: A) -> &mut Self
    where
        A: IntoIterator<Item = (S, ModuleArg)>,
        A::IntoIter: ExactSizeIterator,
        S: AsRef<str>,
    {
        let args = args.into_iter();
        self.bytes.push(0x00);
        module_index.encode(&mut self.bytes);
        args.len().encode(&mut self.bytes);
        for (name, arg) in args {
            name.as_ref().encode(&mut self.bytes);
            arg.encode(&mut self.bytes);
        }
        self.num_added += 1;
        self
    }

    /// Define an instance by exporting core WebAssembly items.
    pub fn export_items<E, S>(&mut self, exports: E) -> &mut Self
    where
        E: IntoIterator<Item = (S, ExportKind, u32)>,
        E::IntoIter: ExactSizeIterator,
        S: AsRef<str>,
    {
        let exports = exports.into_iter();
        self.bytes.push(0x01);
        exports.len().encode(&mut self.bytes);
        for (name, kind, index) in exports {
            name.as_ref().encode(&mut self.bytes);
            kind.encode(&mut self.bytes);
            index.encode(&mut self.bytes);
        }
        self.num_added += 1;
        self
    }
}

impl Encode for InstanceSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl ComponentSection for InstanceSection {
    fn id(&self) -> u8 {
        ComponentSectionId::CoreInstance.into()
    }
}

/// An encoder for the instance section of WebAssembly components.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, ComponentInstanceSection, ComponentExportKind};
///
/// let mut instances = ComponentInstanceSection::new();
/// instances.export_items([("foo", ComponentExportKind::Func, 0)]);
/// instances.instantiate(1, [("foo", ComponentExportKind::Instance, 0)]);
///
/// let mut component = Component::new();
/// component.section(&instances);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct ComponentInstanceSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl ComponentInstanceSection {
    /// Create a new instance section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of instances in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define an instance by instantiating a component.
    pub fn instantiate<A, S>(&mut self, component_index: u32, args: A) -> &mut Self
    where
        A: IntoIterator<Item = (S, ComponentExportKind, u32)>,
        A::IntoIter: ExactSizeIterator,
        S: AsRef<str>,
    {
        let args = args.into_iter();
        self.bytes.push(0x00);
        component_index.encode(&mut self.bytes);
        args.len().encode(&mut self.bytes);
        for (name, kind, index) in args {
            name.as_ref().encode(&mut self.bytes);
            kind.encode(&mut self.bytes);
            index.encode(&mut self.bytes);
        }
        self.num_added += 1;
        self
    }

    /// Define an instance by exporting items.
    pub fn export_items<'a, E>(&mut self, exports: E) -> &mut Self
    where
        E: IntoIterator<Item = (&'a str, ComponentExportKind, u32)>,
        E::IntoIter: ExactSizeIterator,
    {
        let exports = exports.into_iter();
        self.bytes.push(0x01);
        exports.len().encode(&mut self.bytes);
        for (name, kind, index) in exports {
            crate::push_extern_name_byte(&mut self.bytes, name);
            name.encode(&mut self.bytes);
            kind.encode(&mut self.bytes);
            index.encode(&mut self.bytes);
        }
        self.num_added += 1;
        self
    }
}

impl Encode for ComponentInstanceSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl ComponentSection for ComponentInstanceSection {
    fn id(&self) -> u8 {
        ComponentSectionId::Instance.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/modules.rs

Source (jump to first uncovered line)
use crate::{ComponentSection, ComponentSectionId, Encode, Module};

/// An encoder for the module section of WebAssembly components.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Module, Component, ModuleSection};
///
/// let mut module = Module::new();
/// let mut component = Component::new();
/// component.section(&ModuleSection(&module));
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug)]
pub struct ModuleSection<'a>(pub &'a Module);

impl Encode for ModuleSection<'_> {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.0.bytes.encode(sink);
    }
}

impl ComponentSection for ModuleSection<'_> {
    fn id(&self) -> u8 {
        ComponentSectionId::CoreModule.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/names.rs

Source (jump to first uncovered line)
use std::borrow::Cow;

use super::*;
use crate::{encoding_size, ExportKind, NameMap, SectionId};

/// Encoding for the `component-name` custom section which assigns
/// human-readable names to items within a component.
#[derive(Clone, Debug, Default)]
pub struct ComponentNameSection {
    bytes: Vec<u8>,
}

enum Subsection {
    Component,
    Decls,
}

impl ComponentNameSection {
    /// Creates a new blank `name` custom section.
    pub fn new() -> Self {
        Self::default()
    }

    /// Appends a component name subsection to this section.
    ///
    /// This will indicate that the name of the entire component should be the
    /// `name` specified. Note that this should be encoded first before other
    /// subsections.
    pub fn component(&mut self, name: &str) {
        let len = encoding_size(u32::try_from(name.len()).unwrap());
        self.subsection_header(Subsection::Component, len + name.len());
        name.encode(&mut self.bytes);
    }

    /// Appends a decls name subsection to name core functions within the
    /// component.
    pub fn core_funcs(&mut self, names: &NameMap) {
        self.core_decls(ExportKind::Func as u8, names)
    }

    /// Appends a decls name subsection to name core tables within the
    /// component.
    pub fn core_tables(&mut self, names: &NameMap) {
        self.core_decls(ExportKind::Table as u8, names)
    }

    /// Appends a decls name subsection to name core memories within the
    /// component.
    pub fn core_memories(&mut self, names: &NameMap) {
        self.core_decls(ExportKind::Memory as u8, names)
    }

    /// Appends a decls name subsection to name core globals within the
    /// component.
    pub fn core_globals(&mut self, names: &NameMap) {
        self.core_decls(ExportKind::Global as u8, names)
    }

    /// Appends a decls name subsection to name core types within the
    /// component.
    pub fn core_types(&mut self, names: &NameMap) {
        self.core_decls(CORE_TYPE_SORT, names)
    }

    /// Appends a decls name subsection to name core modules within the
    /// component.
    pub fn core_modules(&mut self, names: &NameMap) {
        self.core_decls(CORE_MODULE_SORT, names)
    }

    /// Appends a decls name subsection to name core instances within the
    /// component.
    pub fn core_instances(&mut self, names: &NameMap) {
        self.core_decls(CORE_INSTANCE_SORT, names)
    }

    /// Appends a decls name subsection to name component functions within the
    /// component.
    pub fn funcs(&mut self, names: &NameMap) {
        self.component_decls(FUNCTION_SORT, names)
    }

    /// Appends a decls name subsection to name component values within the
    /// component.
    pub fn values(&mut self, names: &NameMap) {
        self.component_decls(VALUE_SORT, names)
    }

    /// Appends a decls name subsection to name component type within the
    /// component.
    pub fn types(&mut self, names: &NameMap) {
        self.component_decls(TYPE_SORT, names)
    }

    /// Appends a decls name subsection to name components within the
    /// component.
    pub fn components(&mut self, names: &NameMap) {
        self.component_decls(COMPONENT_SORT, names)
    }

    /// Appends a decls name subsection to name component instances within the
    /// component.
    pub fn instances(&mut self, names: &NameMap) {
        self.component_decls(INSTANCE_SORT, names)
    }

    fn component_decls(&mut self, kind: u8, names: &NameMap) {
        self.subsection_header(Subsection::Decls, 1 + names.size());
        self.bytes.push(kind);
        names.encode(&mut self.bytes);
    }

    fn core_decls(&mut self, kind: u8, names: &NameMap) {
        self.subsection_header(Subsection::Decls, 2 + names.size());
        self.bytes.push(CORE_SORT);
        self.bytes.push(kind);
        names.encode(&mut self.bytes);
    }

    fn subsection_header(&mut self, id: Subsection, len: usize) {
        self.bytes.push(id as u8);
        len.encode(&mut self.bytes);
    }

    /// Returns whether this section is empty, or nothing has been encoded.
    pub fn is_empty(&self) -> bool {
        self.bytes.is_empty()
    }

    /// View the encoded section as a CustomSection.
    pub fn as_custom<'a>(&'a self) -> CustomSection<'a> {
        CustomSection {
            name: "component-name".into(),
            data: Cow::Borrowed(&self.bytes),
        }
    }
}

impl Encode for ComponentNameSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.as_custom().encode(sink);
    }
}

impl ComponentSection for ComponentNameSection {
    fn id(&self) -> u8 {
        SectionId::Custom.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/start.rs

Source (jump to first uncovered line)
use crate::{ComponentSection, ComponentSectionId, Encode};

/// An encoder for the start section of WebAssembly components.
///
/// # Example
///
/// ```
/// use wasm_encoder::{Component, ComponentStartSection};
///
/// let start = ComponentStartSection { function_index: 0, args: [0, 1], results: 1 };
///
/// let mut component = Component::new();
/// component.section(&start);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug)]
pub struct ComponentStartSection<A> {
    /// The index to the start function.
    pub function_index: u32,
    /// The arguments to pass to the start function.
    ///
    /// An argument is an index to a value.
    pub args: A,
    /// The number of expected results for the start function.
    ///
    /// This should match the number of results for the type of
    /// the function referenced by `function_index`.
    pub results: u32,
}

impl<A> Encode for ComponentStartSection<A>
where
    A: AsRef<[u32]>,
{
    fn encode(&self, sink: &mut Vec<u8>) {
        let mut bytes = Vec::new();
        self.function_index.encode(&mut bytes);
        self.args.as_ref().encode(&mut bytes);
        self.results.encode(&mut bytes);
        bytes.encode(sink);
    }
}

impl<A> ComponentSection for ComponentStartSection<A>
where
    A: AsRef<[u32]>,
{
    fn id(&self) -> u8 {
        ComponentSectionId::Start.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/component/types.rs

Source (jump to first uncovered line)
use super::CORE_TYPE_SORT;
use crate::{
    encode_section, Alias, ComponentExportKind, ComponentOuterAliasKind, ComponentSection,
    ComponentSectionId, ComponentTypeRef, Encode, EntityType, ValType,
};

/// Represents the type of a core module.
#[derive(Debug, Clone, Default)]
pub struct ModuleType {
    bytes: Vec<u8>,
    num_added: u32,
    types_added: u32,
}

impl ModuleType {
    /// Creates a new core module type.
    pub fn new() -> Self {
        Self::default()
    }

    /// Defines an import in this module type.
    pub fn import(&mut self, module: &str, name: &str, ty: EntityType) -> &mut Self {
        crate::component::imports::push_extern_name_byte(&mut self.bytes, name);
        module.encode(&mut self.bytes);
        name.encode(&mut self.bytes);
        ty.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// Define a type in this module type.
    ///
    /// The returned encoder must be used before adding another definition.
    #[must_use = "the encoder must be used to encode the type"]
    pub fn ty(&mut self) -> CoreTypeEncoder {
        self.bytes.push(0x01);
        self.num_added += 1;
        self.types_added += 1;
        CoreTypeEncoder(&mut self.bytes)
    }

    /// Defines an outer core type alias in this module type.
    pub fn alias_outer_core_type(&mut self, count: u32, index: u32) -> &mut Self {
        self.bytes.push(0x02);
        self.bytes.push(CORE_TYPE_SORT);
        self.bytes.push(0x01); // outer
        count.encode(&mut self.bytes);
        index.encode(&mut self.bytes);
        self.num_added += 1;
        self.types_added += 1;
        self
    }

    /// Defines an export in this module type.
    pub fn export(&mut self, name: &str, ty: EntityType) -> &mut Self {
        self.bytes.push(0x03);
        name.encode(&mut self.bytes);
        ty.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// Gets the number of types that have been added to this module type.
    pub fn type_count(&self) -> u32 {
        self.types_added
    }
}

impl Encode for ModuleType {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.push(0x50);
        self.num_added.encode(sink);
        sink.extend(&self.bytes);
    }
}

/// Used to encode core types.
#[derive(Debug)]
pub struct CoreTypeEncoder<'a>(pub(crate) &'a mut Vec<u8>);

impl<'a> CoreTypeEncoder<'a> {
    /// Define a function type.
    pub fn function<P, R>(self, params: P, results: R)
    where
        P: IntoIterator<Item = ValType>,
        P::IntoIter: ExactSizeIterator,
        R: IntoIterator<Item = ValType>,
        R::IntoIter: ExactSizeIterator,
    {
        let params = params.into_iter();
        let results = results.into_iter();

        self.0.push(0x60);
        params.len().encode(self.0);
        params.for_each(|p| p.encode(self.0));
        results.len().encode(self.0);
        results.for_each(|p| p.encode(self.0));
    }

    /// Define a module type.
    pub fn module(self, ty: &ModuleType) {
        ty.encode(self.0);
    }
}

/// An encoder for the core type section of WebAssembly components.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, CoreTypeSection, ModuleType};
///
/// let mut types = CoreTypeSection::new();
///
/// types.module(&ModuleType::new());
///
/// let mut component = Component::new();
/// component.section(&types);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct CoreTypeSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl CoreTypeSection {
    /// Create a new core type section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of types in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Encode a type into this section.
    ///
    /// The returned encoder must be finished before adding another type.
    #[must_use = "the encoder must be used to encode the type"]
    pub fn ty(&mut self) -> CoreTypeEncoder<'_> {
        self.num_added += 1;
        CoreTypeEncoder(&mut self.bytes)
    }

    /// Define a function type in this type section.
    pub fn function<P, R>(&mut self, params: P, results: R) -> &mut Self
    where
        P: IntoIterator<Item = ValType>,
        P::IntoIter: ExactSizeIterator,
        R: IntoIterator<Item = ValType>,
        R::IntoIter: ExactSizeIterator,
    {
        self.ty().function(params, results);
        self
    }

    /// Define a module type in this type section.
    ///
    /// Currently this is only used for core type sections in components.
    pub fn module(&mut self, ty: &ModuleType) -> &mut Self {
        self.ty().module(ty);
        self
    }
}

impl Encode for CoreTypeSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl ComponentSection for CoreTypeSection {
    fn id(&self) -> u8 {
        ComponentSectionId::CoreType.into()
    }
}

/// Represents a component type.
#[derive(Debug, Clone, Default)]
pub struct ComponentType {
    bytes: Vec<u8>,
    num_added: u32,
    core_types_added: u32,
    types_added: u32,
    instances_added: u32,
}

impl ComponentType {
    /// Creates a new component type.
    pub fn new() -> Self {
        Self::default()
    }

    /// Define a core type in this component type.
    ///
    /// The returned encoder must be used before adding another definition.
    #[must_use = "the encoder must be used to encode the type"]
    pub fn core_type(&mut self) -> CoreTypeEncoder {
        self.bytes.push(0x00);
        self.num_added += 1;
        self.core_types_added += 1;
        CoreTypeEncoder(&mut self.bytes)
    }

    /// Define a type in this component type.
    ///
    /// The returned encoder must be used before adding another definition.
    #[must_use = "the encoder must be used to encode the type"]
    pub fn ty(&mut self) -> ComponentTypeEncoder {
        self.bytes.push(0x01);
        self.num_added += 1;
        self.types_added += 1;
        ComponentTypeEncoder(&mut self.bytes)
    }

    /// Defines an alias for an exported item of a prior instance or an
    /// outer type.
    pub fn alias(&mut self, alias: Alias<'_>) -> &mut Self {
        self.bytes.push(0x02);
        alias.encode(&mut self.bytes);
        self.num_added += 1;
        match &alias {
            Alias::InstanceExport {
                kind: ComponentExportKind::Type,
                ..
            }
            | Alias::Outer {
                kind: ComponentOuterAliasKind::Type,
                ..
            } => self.types_added += 1,
            Alias::Outer {
                kind: ComponentOuterAliasKind::CoreType,
                ..
            } => self.core_types_added += 1,
            Alias::InstanceExport {
                kind: ComponentExportKind::Instance,
                ..
            } => self.instances_added += 1,
            _ => {}
        }
        self
    }

    /// Defines an import in this component type.
    pub fn import(&mut self, name: &str, ty: ComponentTypeRef) -> &mut Self {
        self.bytes.push(0x03);
        crate::component::imports::push_extern_name_byte(&mut self.bytes, name);
        name.encode(&mut self.bytes);
        ty.encode(&mut self.bytes);
        self.num_added += 1;
        match ty {
            ComponentTypeRef::Type(..) => self.types_added += 1,
            ComponentTypeRef::Instance(..) => self.instances_added += 1,
            _ => {}
        }
        self
    }

    /// Defines an export in this component type.
    pub fn export(&mut self, name: &str, ty: ComponentTypeRef) -> &mut Self {
        self.bytes.push(0x04);
        crate::component::imports::push_extern_name_byte(&mut self.bytes, name);
        name.encode(&mut self.bytes);
        ty.encode(&mut self.bytes);
        self.num_added += 1;
        match ty {
            ComponentTypeRef::Type(..) => self.types_added += 1,
            ComponentTypeRef::Instance(..) => self.instances_added += 1,
            _ => {}
        }
        self
    }

    /// Gets the number of core types that have been added to this component type.
    pub fn core_type_count(&self) -> u32 {
        self.core_types_added
    }

    /// Gets the number of types that have been added or aliased in this component type.
    pub fn type_count(&self) -> u32 {
        self.types_added
    }

    /// Gets the number of instances that have been defined in this component
    /// type through imports, exports, or aliases.
    pub fn instance_count(&self) -> u32 {
        self.instances_added
    }
}

impl Encode for ComponentType {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.push(0x41);
        self.num_added.encode(sink);
        sink.extend(&self.bytes);
    }
}

/// Represents an instance type.
#[derive(Debug, Clone, Default)]
pub struct InstanceType(ComponentType);

impl InstanceType {
    /// Creates a new instance type.
    pub fn new() -> Self {
        Self::default()
    }

    /// Define a core type in this instance type.
    ///
    /// The returned encoder must be used before adding another definition.
    #[must_use = "the encoder must be used to encode the type"]
    pub fn core_type(&mut self) -> CoreTypeEncoder {
        self.0.core_type()
    }

    /// Define a type in this instance type.
    ///
    /// The returned encoder must be used before adding another definition.
    #[must_use = "the encoder must be used to encode the type"]
    pub fn ty(&mut self) -> ComponentTypeEncoder {
        self.0.ty()
    }

    /// Defines an outer core type alias in this component type.
    pub fn alias(&mut self, alias: Alias<'_>) -> &mut Self {
        self.0.alias(alias);
        self
    }

    /// Defines an export in this instance type.
    pub fn export(&mut self, name: &str, ty: ComponentTypeRef) -> &mut Self {
        self.0.export(name, ty);
        self
    }

    /// Gets the number of core types that have been added to this instance type.
    pub fn core_type_count(&self) -> u32 {
        self.0.core_types_added
    }

    /// Gets the number of types that have been added or aliased in this instance type.
    pub fn type_count(&self) -> u32 {
        self.0.types_added
    }

    /// Gets the number of instances that have been imported or exported or
    /// aliased in this instance type.
    pub fn instance_count(&self) -> u32 {
        self.0.instances_added
    }

    /// Returns whether or not this instance type is empty.
    pub fn is_empty(&self) -> bool {
        self.0.num_added == 0
    }

    /// Returns the number of entries added to this instance types.
    pub fn len(&self) -> u32 {
        self.0.num_added
    }
}

impl Encode for InstanceType {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.push(0x42);
        self.0.num_added.encode(sink);
        sink.extend(&self.0.bytes);
    }
}

/// Used to encode component function types.
#[derive(Debug)]
pub struct ComponentFuncTypeEncoder<'a>(&'a mut Vec<u8>);

impl<'a> ComponentFuncTypeEncoder<'a> {
    fn new(sink: &'a mut Vec<u8>) -> Self {
        sink.push(0x40);
        Self(sink)
    }

    /// Defines named parameters.
    ///
    /// Parameters must be defined before defining results.
    pub fn params<'b, P, T>(&mut self, params: P) -> &mut Self
    where
        P: IntoIterator<Item = (&'b str, T)>,
        P::IntoIter: ExactSizeIterator,
        T: Into<ComponentValType>,
    {
        let params = params.into_iter();
        params.len().encode(self.0);
        for (name, ty) in params {
            name.encode(self.0);
            ty.into().encode(self.0);
        }
        self
    }

    /// Defines a single unnamed result.
    ///
    /// This method cannot be used with `results`.
    pub fn result(&mut self, ty: impl Into<ComponentValType>) -> &mut Self {
        self.0.push(0x00);
        ty.into().encode(self.0);
        self
    }

    /// Defines named results.
    ///
    /// This method cannot be used with `result`.
    pub fn results<'b, R, T>(&mut self, results: R) -> &mut Self
    where
        R: IntoIterator<Item = (&'b str, T)>,
        R::IntoIter: ExactSizeIterator,
        T: Into<ComponentValType>,
    {
        self.0.push(0x01);
        let results = results.into_iter();
        results.len().encode(self.0);
        for (name, ty) in results {
            name.encode(self.0);
            ty.into().encode(self.0);
        }
        self
    }
}

/// Used to encode component and instance types.
#[derive(Debug)]
pub struct ComponentTypeEncoder<'a>(&'a mut Vec<u8>);

impl<'a> ComponentTypeEncoder<'a> {
    /// Define a component type.
    pub fn component(self, ty: &ComponentType) {
        ty.encode(self.0);
    }

    /// Define an instance type.
    pub fn instance(self, ty: &InstanceType) {
        ty.encode(self.0);
    }

    /// Define a function type.
    pub fn function(self) -> ComponentFuncTypeEncoder<'a> {
        ComponentFuncTypeEncoder::new(self.0)
    }

    /// Define a defined component type.
    ///
    /// The returned encoder must be used before adding another type.
    #[must_use = "the encoder must be used to encode the type"]
    pub fn defined_type(self) -> ComponentDefinedTypeEncoder<'a> {
        ComponentDefinedTypeEncoder(self.0)
    }

    /// Define a resource type.
    pub fn resource(self, rep: ValType, dtor: Option<u32>) {
        self.0.push(0x3f);
        rep.encode(self.0);
        match dtor {
            Some(i) => {
                self.0.push(0x01);
                i.encode(self.0);
            }
            None => self.0.push(0x00),
        }
    }
}

/// Represents a primitive component value type.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum PrimitiveValType {
    /// The type is a boolean.
    Bool,
    /// The type is a signed 8-bit integer.
    S8,
    /// The type is an unsigned 8-bit integer.
    U8,
    /// The type is a signed 16-bit integer.
    S16,
    /// The type is an unsigned 16-bit integer.
    U16,
    /// The type is a signed 32-bit integer.
    S32,
    /// The type is an unsigned 32-bit integer.
    U32,
    /// The type is a signed 64-bit integer.
    S64,
    /// The type is an unsigned 64-bit integer.
    U64,
    /// The type is a 32-bit floating point number with only one NaN.
    F32,
    /// The type is a 64-bit floating point number with only one NaN.
    F64,
    /// The type is a Unicode character.
    Char,
    /// The type is a string.
    String,
}

impl Encode for PrimitiveValType {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.push(match self {
            Self::Bool => 0x7f,
            Self::S8 => 0x7e,
            Self::U8 => 0x7d,
            Self::S16 => 0x7c,
            Self::U16 => 0x7b,
            Self::S32 => 0x7a,
            Self::U32 => 0x79,
            Self::S64 => 0x78,
            Self::U64 => 0x77,
            Self::F32 => 0x76,
            Self::F64 => 0x75,
            Self::Char => 0x74,
            Self::String => 0x73,
        });
    }
}

#[cfg(feature = "wasmparser")]
impl From<wasmparser::PrimitiveValType> for PrimitiveValType {
    fn from(ty: wasmparser::PrimitiveValType) -> Self {
        match ty {
            wasmparser::PrimitiveValType::Bool => PrimitiveValType::Bool,
            wasmparser::PrimitiveValType::S8 => PrimitiveValType::S8,
            wasmparser::PrimitiveValType::U8 => PrimitiveValType::U8,
            wasmparser::PrimitiveValType::S16 => PrimitiveValType::S16,
            wasmparser::PrimitiveValType::U16 => PrimitiveValType::U16,
            wasmparser::PrimitiveValType::S32 => PrimitiveValType::S32,
            wasmparser::PrimitiveValType::U32 => PrimitiveValType::U32,
            wasmparser::PrimitiveValType::S64 => PrimitiveValType::S64,
            wasmparser::PrimitiveValType::U64 => PrimitiveValType::U64,
            wasmparser::PrimitiveValType::F32 => PrimitiveValType::F32,
            wasmparser::PrimitiveValType::F64 => PrimitiveValType::F64,
            wasmparser::PrimitiveValType::Char => PrimitiveValType::Char,
            wasmparser::PrimitiveValType::String => PrimitiveValType::String,
        }
    }
}

/// Represents a component value type.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum ComponentValType {
    /// The value is a primitive type.
    Primitive(PrimitiveValType),
    /// The value is to a defined value type.
    ///
    /// The type index must be to a value type.
    Type(u32),
}

impl Encode for ComponentValType {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            Self::Primitive(ty) => ty.encode(sink),
            Self::Type(index) => (*index as i64).encode(sink),
        }
    }
}

impl From<PrimitiveValType> for ComponentValType {
    fn from(ty: PrimitiveValType) -> Self {
        Self::Primitive(ty)
    }
}

/// Used for encoding component defined types.
#[derive(Debug)]
pub struct ComponentDefinedTypeEncoder<'a>(&'a mut Vec<u8>);

impl ComponentDefinedTypeEncoder<'_> {
    /// Define a primitive value type.
    pub fn primitive(self, ty: PrimitiveValType) {
        ty.encode(self.0);
    }

    /// Define a record type.
    pub fn record<'a, F, T>(self, fields: F)
    where
        F: IntoIterator<Item = (&'a str, T)>,
        F::IntoIter: ExactSizeIterator,
        T: Into<ComponentValType>,
    {
        let fields = fields.into_iter();
        self.0.push(0x72);
        fields.len().encode(self.0);
        for (name, ty) in fields {
            name.encode(self.0);
            ty.into().encode(self.0);
        }
    }

    /// Define a variant type.
    pub fn variant<'a, C>(self, cases: C)
    where
        C: IntoIterator<Item = (&'a str, Option<ComponentValType>, Option<u32>)>,
        C::IntoIter: ExactSizeIterator,
    {
        let cases = cases.into_iter();
        self.0.push(0x71);
        cases.len().encode(self.0);
        for (name, ty, refines) in cases {
            name.encode(self.0);
            ty.encode(self.0);
            refines.encode(self.0);
        }
    }

    /// Define a list type.
    pub fn list(self, ty: impl Into<ComponentValType>) {
        self.0.push(0x70);
        ty.into().encode(self.0);
    }

    /// Define a tuple type.
    pub fn tuple<I, T>(self, types: I)
    where
        I: IntoIterator<Item = T>,
        I::IntoIter: ExactSizeIterator,
        T: Into<ComponentValType>,
    {
        let types = types.into_iter();
        self.0.push(0x6F);
        types.len().encode(self.0);
        for ty in types {
            ty.into().encode(self.0);
        }
    }

    /// Define a flags type.
    pub fn flags<'a, I>(self, names: I)
    where
        I: IntoIterator<Item = &'a str>,
        I::IntoIter: ExactSizeIterator,
    {
        let names = names.into_iter();
        self.0.push(0x6E);
        names.len().encode(self.0);
        for name in names {
            name.encode(self.0);
        }
    }

    /// Define an enum type.
    pub fn enum_type<'a, I>(self, tags: I)
    where
        I: IntoIterator<Item = &'a str>,
        I::IntoIter: ExactSizeIterator,
    {
        let tags = tags.into_iter();
        self.0.push(0x6D);
        tags.len().encode(self.0);
        for tag in tags {
            tag.encode(self.0);
        }
    }

    /// Define an option type.
    pub fn option(self, ty: impl Into<ComponentValType>) {
        self.0.push(0x6B);
        ty.into().encode(self.0);
    }

    /// Define a result type.
    pub fn result(self, ok: Option<ComponentValType>, err: Option<ComponentValType>) {
        self.0.push(0x6A);
        ok.encode(self.0);
        err.encode(self.0);
    }

    /// Define a `own` handle type
    pub fn own(self, idx: u32) {
        self.0.push(0x69);
        idx.encode(self.0);
    }

    /// Define a `borrow` handle type
    pub fn borrow(self, idx: u32) {
        self.0.push(0x68);
        idx.encode(self.0);
    }
}

/// An encoder for the type section of WebAssembly components.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, ComponentTypeSection, PrimitiveValType};
///
/// let mut types = ComponentTypeSection::new();
///
/// // Define a function type of `[string, string] -> string`.
/// types
///   .function()
///   .params(
///     [
///       ("a", PrimitiveValType::String),
///       ("b", PrimitiveValType::String)
///     ]
///   )
///   .result(PrimitiveValType::String);
///
/// let mut component = Component::new();
/// component.section(&types);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct ComponentTypeSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl ComponentTypeSection {
    /// Create a new component type section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of types in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Encode a type into this section.
    ///
    /// The returned encoder must be finished before adding another type.
    #[must_use = "the encoder must be used to encode the type"]
    pub fn ty(&mut self) -> ComponentTypeEncoder<'_> {
        self.num_added += 1;
        ComponentTypeEncoder(&mut self.bytes)
    }

    /// Define a component type in this type section.
    pub fn component(&mut self, ty: &ComponentType) -> &mut Self {
        self.ty().component(ty);
        self
    }

    /// Define an instance type in this type section.
    pub fn instance(&mut self, ty: &InstanceType) -> &mut Self {
        self.ty().instance(ty);
        self
    }

    /// Define a function type in this type section.
    pub fn function(&mut self) -> ComponentFuncTypeEncoder<'_> {
        self.ty().function()
    }

    /// Add a component defined type to this type section.
    ///
    /// The returned encoder must be used before adding another type.
    #[must_use = "the encoder must be used to encode the type"]
    pub fn defined_type(&mut self) -> ComponentDefinedTypeEncoder<'_> {
        self.ty().defined_type()
    }

    /// Defines a new resource type.
    pub fn resource(&mut self, rep: ValType, dtor: Option<u32>) -> &mut Self {
        self.ty().resource(rep, dtor);
        self
    }
}

impl Encode for ComponentTypeSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl ComponentSection for ComponentTypeSection {
    fn id(&self) -> u8 {
        ComponentSectionId::Type.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core.rs

Source (jump to first uncovered line)
mod code;
mod custom;
mod data;
mod dump;
mod elements;
mod exports;
mod functions;
mod globals;
mod imports;
mod linking;
mod memories;
mod names;
mod producers;
mod start;
mod tables;
mod tags;
mod types;

pub use code::*;
pub use custom::*;
pub use data::*;
pub use dump::*;
pub use elements::*;
pub use exports::*;
pub use functions::*;
pub use globals::*;
pub use imports::*;
pub use linking::*;
pub use memories::*;
pub use names::*;
pub use producers::*;
pub use start::*;
pub use tables::*;
pub use tags::*;
pub use types::*;

use crate::Encode;

pub(crate) const CORE_FUNCTION_SORT: u8 = 0x00;
pub(crate) const CORE_TABLE_SORT: u8 = 0x01;
pub(crate) const CORE_MEMORY_SORT: u8 = 0x02;
pub(crate) const CORE_GLOBAL_SORT: u8 = 0x03;
pub(crate) const CORE_TAG_SORT: u8 = 0x04;

/// A WebAssembly module section.
///
/// Various builders defined in this crate already implement this trait, but you
/// can also implement it yourself for your own custom section builders, or use
/// `RawSection` to use a bunch of raw bytes as a section.
pub trait Section: Encode {
    /// Gets the section identifier for this section.
    fn id(&self) -> u8;

    /// Appends this section to the specified destination list of bytes.
    fn append_to(&self, dst: &mut Vec<u8>) {
        dst.push(self.id());
        self.encode(dst);
    }
}

/// Known section identifiers of WebAssembly modules.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd)]
#[repr(u8)]
pub enum SectionId {
    /// The custom section.
    Custom = 0,
    /// The type section.
    Type = 1,
    /// The import section.
    Import = 2,
    /// The function section.
    Function = 3,
    /// The table section.
    Table = 4,
    /// The memory section.
    Memory = 5,
    /// The global section.
    Global = 6,
    /// The export section.
    Export = 7,
    /// The start section.
    Start = 8,
    /// The element section.
    Element = 9,
    /// The code section.
    Code = 10,
    /// The data section.
    Data = 11,
    /// The data count section.
    DataCount = 12,
    /// The tag section.
    ///
    /// This section is supported by the exception handling proposal.
    Tag = 13,
}

impl From<SectionId> for u8 {
    #[inline]
    fn from(id: SectionId) -> u8 {
        id as u8
    }
}

impl Encode for SectionId {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.push(*self as u8);
    }
}

/// Represents a WebAssembly component that is being encoded.
///
/// Sections within a WebAssembly module are encoded in a specific order.
///
/// Modules may also added as a section to a WebAssembly component.
#[derive(Clone, Debug)]
pub struct Module {
    pub(crate) bytes: Vec<u8>,
}

impl Module {
    /// The 8-byte header at the beginning of all core wasm modules.
    #[rustfmt::skip]
    pub const HEADER: [u8; 8] = [
        // Magic
        0x00, 0x61, 0x73, 0x6D,
        // Version
        0x01, 0x00, 0x00, 0x00,
    ];

    /// Begin writing a new `Module`.
    #[rustfmt::skip]
    pub fn new() -> Self {
        Module {
            bytes: Self::HEADER.to_vec(),
        }
    }

    /// Write a section into this module.
    ///
    /// It is your responsibility to define the sections in the [proper
    /// order](https://webassembly.github.io/spec/core/binary/modules.html#binary-module),
    /// and to ensure that each kind of section (other than custom sections) is
    /// only defined once. While this is a potential footgun, it also allows you
    /// to use this crate to easily construct test cases for bad Wasm module
    /// encodings.
    pub fn section(&mut self, section: &impl Section) -> &mut Self {
        self.bytes.push(section.id());
        section.encode(&mut self.bytes);
        self
    }

    /// Get the encoded Wasm module as a slice.
    pub fn as_slice(&self) -> &[u8] {
        &self.bytes
    }

    /// Finish writing this Wasm module and extract ownership of the encoded
    /// bytes.
    pub fn finish(self) -> Vec<u8> {
        self.bytes
    }
}

impl Default for Module {
    fn default() -> Self {
        Self::new()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/code.rs

Source (jump to first uncovered line)
use crate::{encode_section, Encode, HeapType, RefType, Section, SectionId, ValType};
use std::borrow::Cow;

/// An encoder for the code section.
///
/// Code sections are only supported for modules.
///
/// # Example
///
/// ```
/// use wasm_encoder::{
///     CodeSection, Function, FunctionSection, Instruction, Module,
///     TypeSection, ValType
/// };
///
/// let mut types = TypeSection::new();
/// types.function(vec![], vec![ValType::I32]);
///
/// let mut functions = FunctionSection::new();
/// let type_index = 0;
/// functions.function(type_index);
///
/// let locals = vec![];
/// let mut func = Function::new(locals);
/// func.instruction(&Instruction::I32Const(42));
/// let mut code = CodeSection::new();
/// code.function(&func);
///
/// let mut module = Module::new();
/// module
///     .section(&types)
///     .section(&functions)
///     .section(&code);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Default, Debug)]
pub struct CodeSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl CodeSection {
    /// Create a new code section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of functions in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// The number of bytes already added to this section.
    ///
    /// This number doesn't include the vector length that precedes the
    /// code entries, since it has a variable size that isn't known until all
    /// functions are added.
    pub fn byte_len(&self) -> usize {
        self.bytes.len()
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Write a function body into this code section.
    pub fn function(&mut self, func: &Function) -> &mut Self {
        func.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// Add a raw byte slice into this code section as a function body.
    ///
    /// The length prefix of the function body will be automatically prepended,
    /// and should not be included in the raw byte slice.
    ///
    /// # Example
    ///
    /// You can use the `raw` method to copy an already-encoded function body
    /// into a new code section encoder:
    ///
    /// ```
    /// # use wasmparser::{BinaryReader, WasmFeatures, CodeSectionReader};
    /// //                  id, size, # entries, entry
    /// let code_section = [10, 6,    1,         4, 0, 65, 0, 11];
    ///
    /// // Parse the code section.
    /// let reader = BinaryReader::new(&code_section, 0, WasmFeatures::all());
    /// let reader = CodeSectionReader::new(reader).unwrap();
    /// let body = reader.into_iter().next().unwrap().unwrap();
    /// let body_range = body.range();
    ///
    /// // Add the body to a new code section encoder by copying bytes rather
    /// // than re-parsing and re-encoding it.
    /// let mut encoder = wasm_encoder::CodeSection::new();
    /// encoder.raw(&code_section[body_range.start..body_range.end]);
    /// ```
    pub fn raw(&mut self, data: &[u8]) -> &mut Self {
        data.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for CodeSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for CodeSection {
    fn id(&self) -> u8 {
        SectionId::Code.into()
    }
}

/// An encoder for a function body within the code section.
///
/// # Example
///
/// ```
/// use wasm_encoder::{CodeSection, Function, Instruction};
///
/// // Define the function body for:
/// //
/// //     (func (param i32 i32) (result i32)
/// //       local.get 0
/// //       local.get 1
/// //       i32.add)
/// let locals = vec![];
/// let mut func = Function::new(locals);
/// func.instruction(&Instruction::LocalGet(0));
/// func.instruction(&Instruction::LocalGet(1));
/// func.instruction(&Instruction::I32Add);
///
/// // Add our function to the code section.
/// let mut code = CodeSection::new();
/// code.function(&func);
/// ```
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct Function {
    bytes: Vec<u8>,
}

impl Function {
    /// Create a new function body with the given locals.
    ///
    /// The argument is an iterator over `(N, Ty)`, which defines
    /// that the next `N` locals will be of type `Ty`.
    ///
    /// For example, a function with locals 0 and 1 of type I32 and
    /// local 2 of type F32 would be created as:
    ///
    /// ```
    /// # use wasm_encoder::{Function, ValType};
    /// let f = Function::new([(2, ValType::I32), (1, ValType::F32)]);
    /// ```
    ///
    /// For more information about the code section (and function definition) in the WASM binary format
    /// see the [WebAssembly spec](https://webassembly.github.io/spec/core/binary/modules.html#binary-func)
    pub fn new<L>(locals: L) -> Self
    where
        L: IntoIterator<Item = (u32, ValType)>,
        L::IntoIter: ExactSizeIterator,
    {
        let locals = locals.into_iter();
        let mut bytes = vec![];
        locals.len().encode(&mut bytes);
        for (count, ty) in locals {
            count.encode(&mut bytes);
            ty.encode(&mut bytes);
        }
        Function { bytes }
    }

    /// Create a function from a list of locals' types.
    ///
    /// Unlike [`Function::new`], this constructor simply takes a list of types
    /// which are in order associated with locals.
    ///
    /// For example:
    ///
    ///  ```
    /// # use wasm_encoder::{Function, ValType};
    /// let f = Function::new([(2, ValType::I32), (1, ValType::F32)]);
    /// let g = Function::new_with_locals_types([
    ///     ValType::I32, ValType::I32, ValType::F32
    /// ]);
    ///
    /// assert_eq!(f, g)
    /// ```
    pub fn new_with_locals_types<L>(locals: L) -> Self
    where
        L: IntoIterator<Item = ValType>,
    {
        let locals = locals.into_iter();

        let mut locals_collected: Vec<(u32, ValType)> = vec![];
        for l in locals {
            if let Some((last_count, last_type)) = locals_collected.last_mut() {
                if l == *last_type {
                    // Increment the count of consecutive locals of this type
                    *last_count += 1;
                    continue;
                }
            }
            // If we didn't increment, a new type of local appeared
            locals_collected.push((1, l));
        }

        Function::new(locals_collected)
    }

    /// Write an instruction into this function body.
    pub fn instruction(&mut self, instruction: &Instruction) -> &mut Self {
        instruction.encode(&mut self.bytes);
        self
    }

    /// Add raw bytes to this function's body.
    pub fn raw<B>(&mut self, bytes: B) -> &mut Self
    where
        B: IntoIterator<Item = u8>,
    {
        self.bytes.extend(bytes);
        self
    }

    /// The number of bytes already added to this function.
    ///
    /// This number doesn't include the variable-width size field that `encode`
    /// will write before the added bytes, since the size of that field isn't
    /// known until all the instructions are added to this function.
    pub fn byte_len(&self) -> usize {
        self.bytes.len()
    }
}

impl Encode for Function {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.bytes.encode(sink);
    }
}

/// The immediate for a memory instruction.
#[derive(Clone, Copy, Debug)]
pub struct MemArg {
    /// A static offset to add to the instruction's dynamic address operand.
    ///
    /// This is a `u64` field for the memory64 proposal, but 32-bit memories
    /// limit offsets to at most `u32::MAX` bytes. This will be encoded as a LEB
    /// but it won't generate a valid module if an offset is specified which is
    /// larger than the maximum size of the index space for the memory indicated
    /// by `memory_index`.
    pub offset: u64,
    /// The expected alignment of the instruction's dynamic address operand
    /// (expressed the exponent of a power of two).
    pub align: u32,
    /// The index of the memory this instruction is operating upon.
    pub memory_index: u32,
}

impl Encode for MemArg {
    fn encode(&self, sink: &mut Vec<u8>) {
        if self.memory_index == 0 {
            self.align.encode(sink);
            self.offset.encode(sink);
        } else {
            (self.align | (1 << 6)).encode(sink);
            self.memory_index.encode(sink);
            self.offset.encode(sink);
        }
    }
}

/// The memory ordering for atomic instructions.
///
/// For an in-depth explanation of memory orderings, see the C++ documentation
/// for [`memory_order`] or the Rust documentation for [`atomic::Ordering`].
///
/// [`memory_order`]: https://en.cppreference.com/w/cpp/atomic/memory_order
/// [`atomic::Ordering`]: https://doc.rust-lang.org/std/sync/atomic/enum.Ordering.html
#[derive(Clone, Copy, Debug)]
pub enum Ordering {
    /// For a load, it acquires; this orders all operations before the last
    /// "releasing" store. For a store, it releases; this orders all operations
    /// before it at the next "acquiring" load.
    AcqRel,
    /// Like `AcqRel` but all threads see all sequentially consistent operations
    /// in the same order.
    SeqCst,
}

impl Encode for Ordering {
    fn encode(&self, sink: &mut Vec<u8>) {
        let flag: u8 = match self {
            Ordering::SeqCst => 0,
            Ordering::AcqRel => 1,
        };
        sink.push(flag);
    }
}

/// Describe an unchecked SIMD lane index.
pub type Lane = u8;

/// The type for a `block`/`if`/`loop`.
#[derive(Clone, Copy, Debug)]
pub enum BlockType {
    /// `[] -> []`
    Empty,
    /// `[] -> [t]`
    Result(ValType),
    /// The `n`th function type.
    FunctionType(u32),
}

impl Encode for BlockType {
    fn encode(&self, sink: &mut Vec<u8>) {
        match *self {
            Self::Empty => sink.push(0x40),
            Self::Result(ty) => ty.encode(sink),
            Self::FunctionType(f) => (f as i64).encode(sink),
        }
    }
}

/// WebAssembly instructions.
#[derive(Clone, Debug)]
#[non_exhaustive]
#[allow(missing_docs, non_camel_case_types)]
pub enum Instruction<'a> {
    // Control instructions.
    Unreachable,
    Nop,
    Block(BlockType),
    Loop(BlockType),
    If(BlockType),
    Else,
    End,
    Br(u32),
    BrIf(u32),
    BrTable(Cow<'a, [u32]>, u32),
    BrOnNull(u32),
    BrOnNonNull(u32),
    Return,
    Call(u32),
    CallRef(u32),
    CallIndirect {
        ty: u32,
        table: u32,
    },
    ReturnCallRef(u32),
    ReturnCall(u32),
    ReturnCallIndirect {
        ty: u32,
        table: u32,
    },
    TryTable(BlockType, Cow<'a, [Catch]>),
    Throw(u32),
    ThrowRef,

    // Deprecated exception-handling instructions
    Try(BlockType),
    Delegate(u32),
    Catch(u32),
    CatchAll,
    Rethrow(u32),

    // Parametric instructions.
    Drop,
    Select,

    // Variable instructions.
    LocalGet(u32),
    LocalSet(u32),
    LocalTee(u32),
    GlobalGet(u32),
    GlobalSet(u32),

    // Memory instructions.
    I32Load(MemArg),
    I64Load(MemArg),
    F32Load(MemArg),
    F64Load(MemArg),
    I32Load8S(MemArg),
    I32Load8U(MemArg),
    I32Load16S(MemArg),
    I32Load16U(MemArg),
    I64Load8S(MemArg),
    I64Load8U(MemArg),
    I64Load16S(MemArg),
    I64Load16U(MemArg),
    I64Load32S(MemArg),
    I64Load32U(MemArg),
    I32Store(MemArg),
    I64Store(MemArg),
    F32Store(MemArg),
    F64Store(MemArg),
    I32Store8(MemArg),
    I32Store16(MemArg),
    I64Store8(MemArg),
    I64Store16(MemArg),
    I64Store32(MemArg),
    MemorySize(u32),
    MemoryGrow(u32),
    MemoryInit {
        mem: u32,
        data_index: u32,
    },
    DataDrop(u32),
    MemoryCopy {
        src_mem: u32,
        dst_mem: u32,
    },
    MemoryFill(u32),
    MemoryDiscard(u32),

    // Numeric instructions.
    I32Const(i32),
    I64Const(i64),
    F32Const(f32),
    F64Const(f64),
    I32Eqz,
    I32Eq,
    I32Ne,
    I32LtS,
    I32LtU,
    I32GtS,
    I32GtU,
    I32LeS,
    I32LeU,
    I32GeS,
    I32GeU,
    I64Eqz,
    I64Eq,
    I64Ne,
    I64LtS,
    I64LtU,
    I64GtS,
    I64GtU,
    I64LeS,
    I64LeU,
    I64GeS,
    I64GeU,
    F32Eq,
    F32Ne,
    F32Lt,
    F32Gt,
    F32Le,
    F32Ge,
    F64Eq,
    F64Ne,
    F64Lt,
    F64Gt,
    F64Le,
    F64Ge,
    I32Clz,
    I32Ctz,
    I32Popcnt,
    I32Add,
    I32Sub,
    I32Mul,
    I32DivS,
    I32DivU,
    I32RemS,
    I32RemU,
    I32And,
    I32Or,
    I32Xor,
    I32Shl,
    I32ShrS,
    I32ShrU,
    I32Rotl,
    I32Rotr,
    I64Clz,
    I64Ctz,
    I64Popcnt,
    I64Add,
    I64Sub,
    I64Mul,
    I64DivS,
    I64DivU,
    I64RemS,
    I64RemU,
    I64And,
    I64Or,
    I64Xor,
    I64Shl,
    I64ShrS,
    I64ShrU,
    I64Rotl,
    I64Rotr,
    F32Abs,
    F32Neg,
    F32Ceil,
    F32Floor,
    F32Trunc,
    F32Nearest,
    F32Sqrt,
    F32Add,
    F32Sub,
    F32Mul,
    F32Div,
    F32Min,
    F32Max,
    F32Copysign,
    F64Abs,
    F64Neg,
    F64Ceil,
    F64Floor,
    F64Trunc,
    F64Nearest,
    F64Sqrt,
    F64Add,
    F64Sub,
    F64Mul,
    F64Div,
    F64Min,
    F64Max,
    F64Copysign,
    I32WrapI64,
    I32TruncF32S,
    I32TruncF32U,
    I32TruncF64S,
    I32TruncF64U,
    I64ExtendI32S,
    I64ExtendI32U,
    I64TruncF32S,
    I64TruncF32U,
    I64TruncF64S,
    I64TruncF64U,
    F32ConvertI32S,
    F32ConvertI32U,
    F32ConvertI64S,
    F32ConvertI64U,
    F32DemoteF64,
    F64ConvertI32S,
    F64ConvertI32U,
    F64ConvertI64S,
    F64ConvertI64U,
    F64PromoteF32,
    I32ReinterpretF32,
    I64ReinterpretF64,
    F32ReinterpretI32,
    F64ReinterpretI64,
    I32Extend8S,
    I32Extend16S,
    I64Extend8S,
    I64Extend16S,
    I64Extend32S,
    I32TruncSatF32S,
    I32TruncSatF32U,
    I32TruncSatF64S,
    I32TruncSatF64U,
    I64TruncSatF32S,
    I64TruncSatF32U,
    I64TruncSatF64S,
    I64TruncSatF64U,

    // Reference types instructions.
    TypedSelect(ValType),
    RefNull(HeapType),
    RefIsNull,
    RefFunc(u32),
    RefEq,
    RefAsNonNull,

    // GC types instructions.
    StructNew(u32),
    StructNewDefault(u32),
    StructGet {
        struct_type_index: u32,
        field_index: u32,
    },
    StructGetS {
        struct_type_index: u32,
        field_index: u32,
    },
    StructGetU {
        struct_type_index: u32,
        field_index: u32,
    },
    StructSet {
        struct_type_index: u32,
        field_index: u32,
    },

    ArrayNew(u32),
    ArrayNewDefault(u32),
    ArrayNewFixed {
        array_type_index: u32,
        array_size: u32,
    },
    ArrayNewData {
        array_type_index: u32,
        array_data_index: u32,
    },
    ArrayNewElem {
        array_type_index: u32,
        array_elem_index: u32,
    },
    ArrayGet(u32),
    ArrayGetS(u32),
    ArrayGetU(u32),
    ArraySet(u32),
    ArrayLen,
    ArrayFill(u32),
    ArrayCopy {
        array_type_index_dst: u32,
        array_type_index_src: u32,
    },
    ArrayInitData {
        array_type_index: u32,
        array_data_index: u32,
    },
    ArrayInitElem {
        array_type_index: u32,
        array_elem_index: u32,
    },
    RefTestNonNull(HeapType),
    RefTestNullable(HeapType),
    RefCastNonNull(HeapType),
    RefCastNullable(HeapType),
    BrOnCast {
        relative_depth: u32,
        from_ref_type: RefType,
        to_ref_type: RefType,
    },
    BrOnCastFail {
        relative_depth: u32,
        from_ref_type: RefType,
        to_ref_type: RefType,
    },
    AnyConvertExtern,
    ExternConvertAny,

    RefI31,
    I31GetS,
    I31GetU,

    // Bulk memory instructions.
    TableInit {
        elem_index: u32,
        table: u32,
    },
    ElemDrop(u32),
    TableFill(u32),
    TableSet(u32),
    TableGet(u32),
    TableGrow(u32),
    TableSize(u32),
    TableCopy {
        src_table: u32,
        dst_table: u32,
    },

    // SIMD instructions.
    V128Load(MemArg),
    V128Load8x8S(MemArg),
    V128Load8x8U(MemArg),
    V128Load16x4S(MemArg),
    V128Load16x4U(MemArg),
    V128Load32x2S(MemArg),
    V128Load32x2U(MemArg),
    V128Load8Splat(MemArg),
    V128Load16Splat(MemArg),
    V128Load32Splat(MemArg),
    V128Load64Splat(MemArg),
    V128Load32Zero(MemArg),
    V128Load64Zero(MemArg),
    V128Store(MemArg),
    V128Load8Lane {
        memarg: MemArg,
        lane: Lane,
    },
    V128Load16Lane {
        memarg: MemArg,
        lane: Lane,
    },
    V128Load32Lane {
        memarg: MemArg,
        lane: Lane,
    },
    V128Load64Lane {
        memarg: MemArg,
        lane: Lane,
    },
    V128Store8Lane {
        memarg: MemArg,
        lane: Lane,
    },
    V128Store16Lane {
        memarg: MemArg,
        lane: Lane,
    },
    V128Store32Lane {
        memarg: MemArg,
        lane: Lane,
    },
    V128Store64Lane {
        memarg: MemArg,
        lane: Lane,
    },
    V128Const(i128),
    I8x16Shuffle([Lane; 16]),
    I8x16ExtractLaneS(Lane),
    I8x16ExtractLaneU(Lane),
    I8x16ReplaceLane(Lane),
    I16x8ExtractLaneS(Lane),
    I16x8ExtractLaneU(Lane),
    I16x8ReplaceLane(Lane),
    I32x4ExtractLane(Lane),
    I32x4ReplaceLane(Lane),
    I64x2ExtractLane(Lane),
    I64x2ReplaceLane(Lane),
    F32x4ExtractLane(Lane),
    F32x4ReplaceLane(Lane),
    F64x2ExtractLane(Lane),
    F64x2ReplaceLane(Lane),
    I8x16Swizzle,
    I8x16Splat,
    I16x8Splat,
    I32x4Splat,
    I64x2Splat,
    F32x4Splat,
    F64x2Splat,
    I8x16Eq,
    I8x16Ne,
    I8x16LtS,
    I8x16LtU,
    I8x16GtS,
    I8x16GtU,
    I8x16LeS,
    I8x16LeU,
    I8x16GeS,
    I8x16GeU,
    I16x8Eq,
    I16x8Ne,
    I16x8LtS,
    I16x8LtU,
    I16x8GtS,
    I16x8GtU,
    I16x8LeS,
    I16x8LeU,
    I16x8GeS,
    I16x8GeU,
    I32x4Eq,
    I32x4Ne,
    I32x4LtS,
    I32x4LtU,
    I32x4GtS,
    I32x4GtU,
    I32x4LeS,
    I32x4LeU,
    I32x4GeS,
    I32x4GeU,
    I64x2Eq,
    I64x2Ne,
    I64x2LtS,
    I64x2GtS,
    I64x2LeS,
    I64x2GeS,
    F32x4Eq,
    F32x4Ne,
    F32x4Lt,
    F32x4Gt,
    F32x4Le,
    F32x4Ge,
    F64x2Eq,
    F64x2Ne,
    F64x2Lt,
    F64x2Gt,
    F64x2Le,
    F64x2Ge,
    V128Not,
    V128And,
    V128AndNot,
    V128Or,
    V128Xor,
    V128Bitselect,
    V128AnyTrue,
    I8x16Abs,
    I8x16Neg,
    I8x16Popcnt,
    I8x16AllTrue,
    I8x16Bitmask,
    I8x16NarrowI16x8S,
    I8x16NarrowI16x8U,
    I8x16Shl,
    I8x16ShrS,
    I8x16ShrU,
    I8x16Add,
    I8x16AddSatS,
    I8x16AddSatU,
    I8x16Sub,
    I8x16SubSatS,
    I8x16SubSatU,
    I8x16MinS,
    I8x16MinU,
    I8x16MaxS,
    I8x16MaxU,
    I8x16AvgrU,
    I16x8ExtAddPairwiseI8x16S,
    I16x8ExtAddPairwiseI8x16U,
    I16x8Abs,
    I16x8Neg,
    I16x8Q15MulrSatS,
    I16x8AllTrue,
    I16x8Bitmask,
    I16x8NarrowI32x4S,
    I16x8NarrowI32x4U,
    I16x8ExtendLowI8x16S,
    I16x8ExtendHighI8x16S,
    I16x8ExtendLowI8x16U,
    I16x8ExtendHighI8x16U,
    I16x8Shl,
    I16x8ShrS,
    I16x8ShrU,
    I16x8Add,
    I16x8AddSatS,
    I16x8AddSatU,
    I16x8Sub,
    I16x8SubSatS,
    I16x8SubSatU,
    I16x8Mul,
    I16x8MinS,
    I16x8MinU,
    I16x8MaxS,
    I16x8MaxU,
    I16x8AvgrU,
    I16x8ExtMulLowI8x16S,
    I16x8ExtMulHighI8x16S,
    I16x8ExtMulLowI8x16U,
    I16x8ExtMulHighI8x16U,
    I32x4ExtAddPairwiseI16x8S,
    I32x4ExtAddPairwiseI16x8U,
    I32x4Abs,
    I32x4Neg,
    I32x4AllTrue,
    I32x4Bitmask,
    I32x4ExtendLowI16x8S,
    I32x4ExtendHighI16x8S,
    I32x4ExtendLowI16x8U,
    I32x4ExtendHighI16x8U,
    I32x4Shl,
    I32x4ShrS,
    I32x4ShrU,
    I32x4Add,
    I32x4Sub,
    I32x4Mul,
    I32x4MinS,
    I32x4MinU,
    I32x4MaxS,
    I32x4MaxU,
    I32x4DotI16x8S,
    I32x4ExtMulLowI16x8S,
    I32x4ExtMulHighI16x8S,
    I32x4ExtMulLowI16x8U,
    I32x4ExtMulHighI16x8U,
    I64x2Abs,
    I64x2Neg,
    I64x2AllTrue,
    I64x2Bitmask,
    I64x2ExtendLowI32x4S,
    I64x2ExtendHighI32x4S,
    I64x2ExtendLowI32x4U,
    I64x2ExtendHighI32x4U,
    I64x2Shl,
    I64x2ShrS,
    I64x2ShrU,
    I64x2Add,
    I64x2Sub,
    I64x2Mul,
    I64x2ExtMulLowI32x4S,
    I64x2ExtMulHighI32x4S,
    I64x2ExtMulLowI32x4U,
    I64x2ExtMulHighI32x4U,
    F32x4Ceil,
    F32x4Floor,
    F32x4Trunc,
    F32x4Nearest,
    F32x4Abs,
    F32x4Neg,
    F32x4Sqrt,
    F32x4Add,
    F32x4Sub,
    F32x4Mul,
    F32x4Div,
    F32x4Min,
    F32x4Max,
    F32x4PMin,
    F32x4PMax,
    F64x2Ceil,
    F64x2Floor,
    F64x2Trunc,
    F64x2Nearest,
    F64x2Abs,
    F64x2Neg,
    F64x2Sqrt,
    F64x2Add,
    F64x2Sub,
    F64x2Mul,
    F64x2Div,
    F64x2Min,
    F64x2Max,
    F64x2PMin,
    F64x2PMax,
    I32x4TruncSatF32x4S,
    I32x4TruncSatF32x4U,
    F32x4ConvertI32x4S,
    F32x4ConvertI32x4U,
    I32x4TruncSatF64x2SZero,
    I32x4TruncSatF64x2UZero,
    F64x2ConvertLowI32x4S,
    F64x2ConvertLowI32x4U,
    F32x4DemoteF64x2Zero,
    F64x2PromoteLowF32x4,

    // Relaxed simd proposal
    I8x16RelaxedSwizzle,
    I32x4RelaxedTruncF32x4S,
    I32x4RelaxedTruncF32x4U,
    I32x4RelaxedTruncF64x2SZero,
    I32x4RelaxedTruncF64x2UZero,
    F32x4RelaxedMadd,
    F32x4RelaxedNmadd,
    F64x2RelaxedMadd,
    F64x2RelaxedNmadd,
    I8x16RelaxedLaneselect,
    I16x8RelaxedLaneselect,
    I32x4RelaxedLaneselect,
    I64x2RelaxedLaneselect,
    F32x4RelaxedMin,
    F32x4RelaxedMax,
    F64x2RelaxedMin,
    F64x2RelaxedMax,
    I16x8RelaxedQ15mulrS,
    I16x8RelaxedDotI8x16I7x16S,
    I32x4RelaxedDotI8x16I7x16AddS,

    // Atomic instructions (the threads proposal)
    MemoryAtomicNotify(MemArg),
    MemoryAtomicWait32(MemArg),
    MemoryAtomicWait64(MemArg),
    AtomicFence,
    I32AtomicLoad(MemArg),
    I64AtomicLoad(MemArg),
    I32AtomicLoad8U(MemArg),
    I32AtomicLoad16U(MemArg),
    I64AtomicLoad8U(MemArg),
    I64AtomicLoad16U(MemArg),
    I64AtomicLoad32U(MemArg),
    I32AtomicStore(MemArg),
    I64AtomicStore(MemArg),
    I32AtomicStore8(MemArg),
    I32AtomicStore16(MemArg),
    I64AtomicStore8(MemArg),
    I64AtomicStore16(MemArg),
    I64AtomicStore32(MemArg),
    I32AtomicRmwAdd(MemArg),
    I64AtomicRmwAdd(MemArg),
    I32AtomicRmw8AddU(MemArg),
    I32AtomicRmw16AddU(MemArg),
    I64AtomicRmw8AddU(MemArg),
    I64AtomicRmw16AddU(MemArg),
    I64AtomicRmw32AddU(MemArg),
    I32AtomicRmwSub(MemArg),
    I64AtomicRmwSub(MemArg),
    I32AtomicRmw8SubU(MemArg),
    I32AtomicRmw16SubU(MemArg),
    I64AtomicRmw8SubU(MemArg),
    I64AtomicRmw16SubU(MemArg),
    I64AtomicRmw32SubU(MemArg),
    I32AtomicRmwAnd(MemArg),
    I64AtomicRmwAnd(MemArg),
    I32AtomicRmw8AndU(MemArg),
    I32AtomicRmw16AndU(MemArg),
    I64AtomicRmw8AndU(MemArg),
    I64AtomicRmw16AndU(MemArg),
    I64AtomicRmw32AndU(MemArg),
    I32AtomicRmwOr(MemArg),
    I64AtomicRmwOr(MemArg),
    I32AtomicRmw8OrU(MemArg),
    I32AtomicRmw16OrU(MemArg),
    I64AtomicRmw8OrU(MemArg),
    I64AtomicRmw16OrU(MemArg),
    I64AtomicRmw32OrU(MemArg),
    I32AtomicRmwXor(MemArg),
    I64AtomicRmwXor(MemArg),
    I32AtomicRmw8XorU(MemArg),
    I32AtomicRmw16XorU(MemArg),
    I64AtomicRmw8XorU(MemArg),
    I64AtomicRmw16XorU(MemArg),
    I64AtomicRmw32XorU(MemArg),
    I32AtomicRmwXchg(MemArg),
    I64AtomicRmwXchg(MemArg),
    I32AtomicRmw8XchgU(MemArg),
    I32AtomicRmw16XchgU(MemArg),
    I64AtomicRmw8XchgU(MemArg),
    I64AtomicRmw16XchgU(MemArg),
    I64AtomicRmw32XchgU(MemArg),
    I32AtomicRmwCmpxchg(MemArg),
    I64AtomicRmwCmpxchg(MemArg),
    I32AtomicRmw8CmpxchgU(MemArg),
    I32AtomicRmw16CmpxchgU(MemArg),
    I64AtomicRmw8CmpxchgU(MemArg),
    I64AtomicRmw16CmpxchgU(MemArg),
    I64AtomicRmw32CmpxchgU(MemArg),

    // More atomic instructions (the shared-everything-threads proposal)
    GlobalAtomicGet {
        ordering: Ordering,
        global_index: u32,
    },
    GlobalAtomicSet {
        ordering: Ordering,
        global_index: u32,
    },
    GlobalAtomicRmwAdd {
        ordering: Ordering,
        global_index: u32,
    },
    GlobalAtomicRmwSub {
        ordering: Ordering,
        global_index: u32,
    },
    GlobalAtomicRmwAnd {
        ordering: Ordering,
        global_index: u32,
    },
    GlobalAtomicRmwOr {
        ordering: Ordering,
        global_index: u32,
    },
    GlobalAtomicRmwXor {
        ordering: Ordering,
        global_index: u32,
    },
    GlobalAtomicRmwXchg {
        ordering: Ordering,
        global_index: u32,
    },
    GlobalAtomicRmwCmpxchg {
        ordering: Ordering,
        global_index: u32,
    },
}

impl Encode for Instruction<'_> {
    fn encode(&self, sink: &mut Vec<u8>) {
        match *self {
            // Control instructions.
            Instruction::Unreachable => sink.push(0x00),
            Instruction::Nop => sink.push(0x01),
            Instruction::Block(bt) => {
                sink.push(0x02);
                bt.encode(sink);
            }
            Instruction::Loop(bt) => {
                sink.push(0x03);
                bt.encode(sink);
            }
            Instruction::If(bt) => {
                sink.push(0x04);
                bt.encode(sink);
            }
            Instruction::Else => sink.push(0x05),
            Instruction::Try(bt) => {
                sink.push(0x06);
                bt.encode(sink);
            }
            Instruction::Catch(t) => {
                sink.push(0x07);
                t.encode(sink);
            }
            Instruction::Throw(t) => {
                sink.push(0x08);
                t.encode(sink);
            }
            Instruction::Rethrow(l) => {
                sink.push(0x09);
                l.encode(sink);
            }
            Instruction::ThrowRef => {
                sink.push(0x0A);
            }
            Instruction::End => sink.push(0x0B),
            Instruction::Br(l) => {
                sink.push(0x0C);
                l.encode(sink);
            }
            Instruction::BrIf(l) => {
                sink.push(0x0D);
                l.encode(sink);
            }
            Instruction::BrTable(ref ls, l) => {
                sink.push(0x0E);
                ls.encode(sink);
                l.encode(sink);
            }
            Instruction::BrOnNull(l) => {
                sink.push(0xD5);
                l.encode(sink);
            }
            Instruction::BrOnNonNull(l) => {
                sink.push(0xD6);
                l.encode(sink);
            }
            Instruction::Return => sink.push(0x0F),
            Instruction::Call(f) => {
                sink.push(0x10);
                f.encode(sink);
            }
            Instruction::CallRef(ty) => {
                sink.push(0x14);
                ty.encode(sink);
            }
            Instruction::CallIndirect { ty, table } => {
                sink.push(0x11);
                ty.encode(sink);
                table.encode(sink);
            }
            Instruction::ReturnCallRef(ty) => {
                sink.push(0x15);
                ty.encode(sink);
            }

            Instruction::ReturnCall(f) => {
                sink.push(0x12);
                f.encode(sink);
            }
            Instruction::ReturnCallIndirect { ty, table } => {
                sink.push(0x13);
                ty.encode(sink);
                table.encode(sink);
            }
            Instruction::Delegate(l) => {
                sink.push(0x18);
                l.encode(sink);
            }
            Instruction::CatchAll => {
                sink.push(0x19);
            }

            // Parametric instructions.
            Instruction::Drop => sink.push(0x1A),
            Instruction::Select => sink.push(0x1B),
            Instruction::TypedSelect(ty) => {
                sink.push(0x1c);
                [ty].encode(sink);
            }

            Instruction::TryTable(ty, ref catches) => {
                sink.push(0x1f);
                ty.encode(sink);
                catches.encode(sink);
            }

            // Variable instructions.
            Instruction::LocalGet(l) => {
                sink.push(0x20);
                l.encode(sink);
            }
            Instruction::LocalSet(l) => {
                sink.push(0x21);
                l.encode(sink);
            }
            Instruction::LocalTee(l) => {
                sink.push(0x22);
                l.encode(sink);
            }
            Instruction::GlobalGet(g) => {
                sink.push(0x23);
                g.encode(sink);
            }
            Instruction::GlobalSet(g) => {
                sink.push(0x24);
                g.encode(sink);
            }
            Instruction::TableGet(table) => {
                sink.push(0x25);
                table.encode(sink);
            }
            Instruction::TableSet(table) => {
                sink.push(0x26);
                table.encode(sink);
            }

            // Memory instructions.
            Instruction::I32Load(m) => {
                sink.push(0x28);
                m.encode(sink);
            }
            Instruction::I64Load(m) => {
                sink.push(0x29);
                m.encode(sink);
            }
            Instruction::F32Load(m) => {
                sink.push(0x2A);
                m.encode(sink);
            }
            Instruction::F64Load(m) => {
                sink.push(0x2B);
                m.encode(sink);
            }
            Instruction::I32Load8S(m) => {
                sink.push(0x2C);
                m.encode(sink);
            }
            Instruction::I32Load8U(m) => {
                sink.push(0x2D);
                m.encode(sink);
            }
            Instruction::I32Load16S(m) => {
                sink.push(0x2E);
                m.encode(sink);
            }
            Instruction::I32Load16U(m) => {
                sink.push(0x2F);
                m.encode(sink);
            }
            Instruction::I64Load8S(m) => {
                sink.push(0x30);
                m.encode(sink);
            }
            Instruction::I64Load8U(m) => {
                sink.push(0x31);
                m.encode(sink);
            }
            Instruction::I64Load16S(m) => {
                sink.push(0x32);
                m.encode(sink);
            }
            Instruction::I64Load16U(m) => {
                sink.push(0x33);
                m.encode(sink);
            }
            Instruction::I64Load32S(m) => {
                sink.push(0x34);
                m.encode(sink);
            }
            Instruction::I64Load32U(m) => {
                sink.push(0x35);
                m.encode(sink);
            }
            Instruction::I32Store(m) => {
                sink.push(0x36);
                m.encode(sink);
            }
            Instruction::I64Store(m) => {
                sink.push(0x37);
                m.encode(sink);
            }
            Instruction::F32Store(m) => {
                sink.push(0x38);
                m.encode(sink);
            }
            Instruction::F64Store(m) => {
                sink.push(0x39);
                m.encode(sink);
            }
            Instruction::I32Store8(m) => {
                sink.push(0x3A);
                m.encode(sink);
            }
            Instruction::I32Store16(m) => {
                sink.push(0x3B);
                m.encode(sink);
            }
            Instruction::I64Store8(m) => {
                sink.push(0x3C);
                m.encode(sink);
            }
            Instruction::I64Store16(m) => {
                sink.push(0x3D);
                m.encode(sink);
            }
            Instruction::I64Store32(m) => {
                sink.push(0x3E);
                m.encode(sink);
            }
            Instruction::MemorySize(i) => {
                sink.push(0x3F);
                i.encode(sink);
            }
            Instruction::MemoryGrow(i) => {
                sink.push(0x40);
                i.encode(sink);
            }
            Instruction::MemoryInit { mem, data_index } => {
                sink.push(0xfc);
                sink.push(0x08);
                data_index.encode(sink);
                mem.encode(sink);
            }
            Instruction::DataDrop(data) => {
                sink.push(0xfc);
                sink.push(0x09);
                data.encode(sink);
            }
            Instruction::MemoryCopy { src_mem, dst_mem } => {
                sink.push(0xfc);
                sink.push(0x0a);
                dst_mem.encode(sink);
                src_mem.encode(sink);
            }
            Instruction::MemoryFill(mem) => {
                sink.push(0xfc);
                sink.push(0x0b);
                mem.encode(sink);
            }
            Instruction::MemoryDiscard(mem) => {
                sink.push(0xfc);
                sink.push(0x12);
                mem.encode(sink);
            }

            // Numeric instructions.
            Instruction::I32Const(x) => {
                sink.push(0x41);
                x.encode(sink);
            }
            Instruction::I64Const(x) => {
                sink.push(0x42);
                x.encode(sink);
            }
            Instruction::F32Const(x) => {
                sink.push(0x43);
                let x = x.to_bits();
                sink.extend(x.to_le_bytes().iter().copied());
            }
            Instruction::F64Const(x) => {
                sink.push(0x44);
                let x = x.to_bits();
                sink.extend(x.to_le_bytes().iter().copied());
            }
            Instruction::I32Eqz => sink.push(0x45),
            Instruction::I32Eq => sink.push(0x46),
            Instruction::I32Ne => sink.push(0x47),
            Instruction::I32LtS => sink.push(0x48),
            Instruction::I32LtU => sink.push(0x49),
            Instruction::I32GtS => sink.push(0x4A),
            Instruction::I32GtU => sink.push(0x4B),
            Instruction::I32LeS => sink.push(0x4C),
            Instruction::I32LeU => sink.push(0x4D),
            Instruction::I32GeS => sink.push(0x4E),
            Instruction::I32GeU => sink.push(0x4F),
            Instruction::I64Eqz => sink.push(0x50),
            Instruction::I64Eq => sink.push(0x51),
            Instruction::I64Ne => sink.push(0x52),
            Instruction::I64LtS => sink.push(0x53),
            Instruction::I64LtU => sink.push(0x54),
            Instruction::I64GtS => sink.push(0x55),
            Instruction::I64GtU => sink.push(0x56),
            Instruction::I64LeS => sink.push(0x57),
            Instruction::I64LeU => sink.push(0x58),
            Instruction::I64GeS => sink.push(0x59),
            Instruction::I64GeU => sink.push(0x5A),
            Instruction::F32Eq => sink.push(0x5B),
            Instruction::F32Ne => sink.push(0x5C),
            Instruction::F32Lt => sink.push(0x5D),
            Instruction::F32Gt => sink.push(0x5E),
            Instruction::F32Le => sink.push(0x5F),
            Instruction::F32Ge => sink.push(0x60),
            Instruction::F64Eq => sink.push(0x61),
            Instruction::F64Ne => sink.push(0x62),
            Instruction::F64Lt => sink.push(0x63),
            Instruction::F64Gt => sink.push(0x64),
            Instruction::F64Le => sink.push(0x65),
            Instruction::F64Ge => sink.push(0x66),
            Instruction::I32Clz => sink.push(0x67),
            Instruction::I32Ctz => sink.push(0x68),
            Instruction::I32Popcnt => sink.push(0x69),
            Instruction::I32Add => sink.push(0x6A),
            Instruction::I32Sub => sink.push(0x6B),
            Instruction::I32Mul => sink.push(0x6C),
            Instruction::I32DivS => sink.push(0x6D),
            Instruction::I32DivU => sink.push(0x6E),
            Instruction::I32RemS => sink.push(0x6F),
            Instruction::I32RemU => sink.push(0x70),
            Instruction::I32And => sink.push(0x71),
            Instruction::I32Or => sink.push(0x72),
            Instruction::I32Xor => sink.push(0x73),
            Instruction::I32Shl => sink.push(0x74),
            Instruction::I32ShrS => sink.push(0x75),
            Instruction::I32ShrU => sink.push(0x76),
            Instruction::I32Rotl => sink.push(0x77),
            Instruction::I32Rotr => sink.push(0x78),
            Instruction::I64Clz => sink.push(0x79),
            Instruction::I64Ctz => sink.push(0x7A),
            Instruction::I64Popcnt => sink.push(0x7B),
            Instruction::I64Add => sink.push(0x7C),
            Instruction::I64Sub => sink.push(0x7D),
            Instruction::I64Mul => sink.push(0x7E),
            Instruction::I64DivS => sink.push(0x7F),
            Instruction::I64DivU => sink.push(0x80),
            Instruction::I64RemS => sink.push(0x81),
            Instruction::I64RemU => sink.push(0x82),
            Instruction::I64And => sink.push(0x83),
            Instruction::I64Or => sink.push(0x84),
            Instruction::I64Xor => sink.push(0x85),
            Instruction::I64Shl => sink.push(0x86),
            Instruction::I64ShrS => sink.push(0x87),
            Instruction::I64ShrU => sink.push(0x88),
            Instruction::I64Rotl => sink.push(0x89),
            Instruction::I64Rotr => sink.push(0x8A),
            Instruction::F32Abs => sink.push(0x8B),
            Instruction::F32Neg => sink.push(0x8C),
            Instruction::F32Ceil => sink.push(0x8D),
            Instruction::F32Floor => sink.push(0x8E),
            Instruction::F32Trunc => sink.push(0x8F),
            Instruction::F32Nearest => sink.push(0x90),
            Instruction::F32Sqrt => sink.push(0x91),
            Instruction::F32Add => sink.push(0x92),
            Instruction::F32Sub => sink.push(0x93),
            Instruction::F32Mul => sink.push(0x94),
            Instruction::F32Div => sink.push(0x95),
            Instruction::F32Min => sink.push(0x96),
            Instruction::F32Max => sink.push(0x97),
            Instruction::F32Copysign => sink.push(0x98),
            Instruction::F64Abs => sink.push(0x99),
            Instruction::F64Neg => sink.push(0x9A),
            Instruction::F64Ceil => sink.push(0x9B),
            Instruction::F64Floor => sink.push(0x9C),
            Instruction::F64Trunc => sink.push(0x9D),
            Instruction::F64Nearest => sink.push(0x9E),
            Instruction::F64Sqrt => sink.push(0x9F),
            Instruction::F64Add => sink.push(0xA0),
            Instruction::F64Sub => sink.push(0xA1),
            Instruction::F64Mul => sink.push(0xA2),
            Instruction::F64Div => sink.push(0xA3),
            Instruction::F64Min => sink.push(0xA4),
            Instruction::F64Max => sink.push(0xA5),
            Instruction::F64Copysign => sink.push(0xA6),
            Instruction::I32WrapI64 => sink.push(0xA7),
            Instruction::I32TruncF32S => sink.push(0xA8),
            Instruction::I32TruncF32U => sink.push(0xA9),
            Instruction::I32TruncF64S => sink.push(0xAA),
            Instruction::I32TruncF64U => sink.push(0xAB),
            Instruction::I64ExtendI32S => sink.push(0xAC),
            Instruction::I64ExtendI32U => sink.push(0xAD),
            Instruction::I64TruncF32S => sink.push(0xAE),
            Instruction::I64TruncF32U => sink.push(0xAF),
            Instruction::I64TruncF64S => sink.push(0xB0),
            Instruction::I64TruncF64U => sink.push(0xB1),
            Instruction::F32ConvertI32S => sink.push(0xB2),
            Instruction::F32ConvertI32U => sink.push(0xB3),
            Instruction::F32ConvertI64S => sink.push(0xB4),
            Instruction::F32ConvertI64U => sink.push(0xB5),
            Instruction::F32DemoteF64 => sink.push(0xB6),
            Instruction::F64ConvertI32S => sink.push(0xB7),
            Instruction::F64ConvertI32U => sink.push(0xB8),
            Instruction::F64ConvertI64S => sink.push(0xB9),
            Instruction::F64ConvertI64U => sink.push(0xBA),
            Instruction::F64PromoteF32 => sink.push(0xBB),
            Instruction::I32ReinterpretF32 => sink.push(0xBC),
            Instruction::I64ReinterpretF64 => sink.push(0xBD),
            Instruction::F32ReinterpretI32 => sink.push(0xBE),
            Instruction::F64ReinterpretI64 => sink.push(0xBF),
            Instruction::I32Extend8S => sink.push(0xC0),
            Instruction::I32Extend16S => sink.push(0xC1),
            Instruction::I64Extend8S => sink.push(0xC2),
            Instruction::I64Extend16S => sink.push(0xC3),
            Instruction::I64Extend32S => sink.push(0xC4),

            Instruction::I32TruncSatF32S => {
                sink.push(0xFC);
                sink.push(0x00);
            }
            Instruction::I32TruncSatF32U => {
                sink.push(0xFC);
                sink.push(0x01);
            }
            Instruction::I32TruncSatF64S => {
                sink.push(0xFC);
                sink.push(0x02);
            }
            Instruction::I32TruncSatF64U => {
                sink.push(0xFC);
                sink.push(0x03);
            }
            Instruction::I64TruncSatF32S => {
                sink.push(0xFC);
                sink.push(0x04);
            }
            Instruction::I64TruncSatF32U => {
                sink.push(0xFC);
                sink.push(0x05);
            }
            Instruction::I64TruncSatF64S => {
                sink.push(0xFC);
                sink.push(0x06);
            }
            Instruction::I64TruncSatF64U => {
                sink.push(0xFC);
                sink.push(0x07);
            }

            // Reference types instructions.
            Instruction::RefNull(ty) => {
                sink.push(0xd0);
                ty.encode(sink);
            }
            Instruction::RefIsNull => sink.push(0xd1),
            Instruction::RefFunc(f) => {
                sink.push(0xd2);
                f.encode(sink);
            }
            Instruction::RefEq => sink.push(0xd3),
            Instruction::RefAsNonNull => sink.push(0xd4),

            // GC instructions.
            Instruction::StructNew(type_index) => {
                sink.push(0xfb);
                sink.push(0x00);
                type_index.encode(sink);
            }
            Instruction::StructNewDefault(type_index) => {
                sink.push(0xfb);
                sink.push(0x01);
                type_index.encode(sink);
            }
            Instruction::StructGet {
                struct_type_index,
                field_index,
            } => {
                sink.push(0xfb);
                sink.push(0x02);
                struct_type_index.encode(sink);
                field_index.encode(sink);
            }
            Instruction::StructGetS {
                struct_type_index,
                field_index,
            } => {
                sink.push(0xfb);
                sink.push(0x03);
                struct_type_index.encode(sink);
                field_index.encode(sink);
            }
            Instruction::StructGetU {
                struct_type_index,
                field_index,
            } => {
                sink.push(0xfb);
                sink.push(0x04);
                struct_type_index.encode(sink);
                field_index.encode(sink);
            }
            Instruction::StructSet {
                struct_type_index,
                field_index,
            } => {
                sink.push(0xfb);
                sink.push(0x05);
                struct_type_index.encode(sink);
                field_index.encode(sink);
            }
            Instruction::ArrayNew(type_index) => {
                sink.push(0xfb);
                sink.push(0x06);
                type_index.encode(sink);
            }
            Instruction::ArrayNewDefault(type_index) => {
                sink.push(0xfb);
                sink.push(0x07);
                type_index.encode(sink);
            }
            Instruction::ArrayNewFixed {
                array_type_index,
                array_size,
            } => {
                sink.push(0xfb);
                sink.push(0x08);
                array_type_index.encode(sink);
                array_size.encode(sink);
            }
            Instruction::ArrayNewData {
                array_type_index,
                array_data_index,
            } => {
                sink.push(0xfb);
                sink.push(0x09);
                array_type_index.encode(sink);
                array_data_index.encode(sink);
            }
            Instruction::ArrayNewElem {
                array_type_index,
                array_elem_index,
            } => {
                sink.push(0xfb);
                sink.push(0x0a);
                array_type_index.encode(sink);
                array_elem_index.encode(sink);
            }
            Instruction::ArrayGet(type_index) => {
                sink.push(0xfb);
                sink.push(0x0b);
                type_index.encode(sink);
            }
            Instruction::ArrayGetS(type_index) => {
                sink.push(0xfb);
                sink.push(0x0c);
                type_index.encode(sink);
            }
            Instruction::ArrayGetU(type_index) => {
                sink.push(0xfb);
                sink.push(0x0d);
                type_index.encode(sink);
            }
            Instruction::ArraySet(type_index) => {
                sink.push(0xfb);
                sink.push(0x0e);
                type_index.encode(sink);
            }
            Instruction::ArrayLen => {
                sink.push(0xfb);
                sink.push(0x0f);
            }
            Instruction::ArrayFill(type_index) => {
                sink.push(0xfb);
                sink.push(0x10);
                type_index.encode(sink);
            }
            Instruction::ArrayCopy {
                array_type_index_dst,
                array_type_index_src,
            } => {
                sink.push(0xfb);
                sink.push(0x11);
                array_type_index_dst.encode(sink);
                array_type_index_src.encode(sink);
            }
            Instruction::ArrayInitData {
                array_type_index,
                array_data_index,
            } => {
                sink.push(0xfb);
                sink.push(0x12);
                array_type_index.encode(sink);
                array_data_index.encode(sink);
            }
            Instruction::ArrayInitElem {
                array_type_index,
                array_elem_index,
            } => {
                sink.push(0xfb);
                sink.push(0x13);
                array_type_index.encode(sink);
                array_elem_index.encode(sink);
            }
            Instruction::RefTestNonNull(heap_type) => {
                sink.push(0xfb);
                sink.push(0x14);
                heap_type.encode(sink);
            }
            Instruction::RefTestNullable(heap_type) => {
                sink.push(0xfb);
                sink.push(0x15);
                heap_type.encode(sink);
            }
            Instruction::RefCastNonNull(heap_type) => {
                sink.push(0xfb);
                sink.push(0x16);
                heap_type.encode(sink);
            }
            Instruction::RefCastNullable(heap_type) => {
                sink.push(0xfb);
                sink.push(0x17);
                heap_type.encode(sink);
            }
            Instruction::BrOnCast {
                relative_depth,
                from_ref_type,
                to_ref_type,
            } => {
                sink.push(0xfb);
                sink.push(0x18);
                let cast_flags =
                    (from_ref_type.nullable as u8) | ((to_ref_type.nullable as u8) << 1);
                sink.push(cast_flags);
                relative_depth.encode(sink);
                from_ref_type.heap_type.encode(sink);
                to_ref_type.heap_type.encode(sink);
            }
            Instruction::BrOnCastFail {
                relative_depth,
                from_ref_type,
                to_ref_type,
            } => {
                sink.push(0xfb);
                sink.push(0x19);
                let cast_flags =
                    (from_ref_type.nullable as u8) | ((to_ref_type.nullable as u8) << 1);
                sink.push(cast_flags);
                relative_depth.encode(sink);
                from_ref_type.heap_type.encode(sink);
                to_ref_type.heap_type.encode(sink);
            }
            Instruction::AnyConvertExtern => {
                sink.push(0xfb);
                sink.push(0x1a);
            }
            Instruction::ExternConvertAny => {
                sink.push(0xfb);
                sink.push(0x1b);
            }
            Instruction::RefI31 => {
                sink.push(0xfb);
                sink.push(0x1c);
            }
            Instruction::I31GetS => {
                sink.push(0xfb);
                sink.push(0x1d);
            }
            Instruction::I31GetU => {
                sink.push(0xfb);
                sink.push(0x1e);
            }

            // Bulk memory instructions.
            Instruction::TableInit { elem_index, table } => {
                sink.push(0xfc);
                sink.push(0x0c);
                elem_index.encode(sink);
                table.encode(sink);
            }
            Instruction::ElemDrop(segment) => {
                sink.push(0xfc);
                sink.push(0x0d);
                segment.encode(sink);
            }
            Instruction::TableCopy {
                src_table,
                dst_table,
            } => {
                sink.push(0xfc);
                sink.push(0x0e);
                dst_table.encode(sink);
                src_table.encode(sink);
            }
            Instruction::TableGrow(table) => {
                sink.push(0xfc);
                sink.push(0x0f);
                table.encode(sink);
            }
            Instruction::TableSize(table) => {
                sink.push(0xfc);
                sink.push(0x10);
                table.encode(sink);
            }
            Instruction::TableFill(table) => {
                sink.push(0xfc);
                sink.push(0x11);
                table.encode(sink);
            }

            // SIMD instructions.
            Instruction::V128Load(memarg) => {
                sink.push(0xFD);
                0x00u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load8x8S(memarg) => {
                sink.push(0xFD);
                0x01u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load8x8U(memarg) => {
                sink.push(0xFD);
                0x02u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load16x4S(memarg) => {
                sink.push(0xFD);
                0x03u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load16x4U(memarg) => {
                sink.push(0xFD);
                0x04u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load32x2S(memarg) => {
                sink.push(0xFD);
                0x05u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load32x2U(memarg) => {
                sink.push(0xFD);
                0x06u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load8Splat(memarg) => {
                sink.push(0xFD);
                0x07u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load16Splat(memarg) => {
                sink.push(0xFD);
                0x08u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load32Splat(memarg) => {
                sink.push(0xFD);
                0x09u32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load64Splat(memarg) => {
                sink.push(0xFD);
                0x0Au32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Store(memarg) => {
                sink.push(0xFD);
                0x0Bu32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Const(x) => {
                sink.push(0xFD);
                0x0Cu32.encode(sink);
                sink.extend(x.to_le_bytes().iter().copied());
            }
            Instruction::I8x16Shuffle(lanes) => {
                sink.push(0xFD);
                0x0Du32.encode(sink);
                assert!(lanes.iter().all(|l: &u8| *l < 32));
                sink.extend(lanes.iter().copied());
            }
            Instruction::I8x16Swizzle => {
                sink.push(0xFD);
                0x0Eu32.encode(sink);
            }
            Instruction::I8x16Splat => {
                sink.push(0xFD);
                0x0Fu32.encode(sink);
            }
            Instruction::I16x8Splat => {
                sink.push(0xFD);
                0x10u32.encode(sink);
            }
            Instruction::I32x4Splat => {
                sink.push(0xFD);
                0x11u32.encode(sink);
            }
            Instruction::I64x2Splat => {
                sink.push(0xFD);
                0x12u32.encode(sink);
            }
            Instruction::F32x4Splat => {
                sink.push(0xFD);
                0x13u32.encode(sink);
            }
            Instruction::F64x2Splat => {
                sink.push(0xFD);
                0x14u32.encode(sink);
            }
            Instruction::I8x16ExtractLaneS(lane) => {
                sink.push(0xFD);
                0x15u32.encode(sink);
                assert!(lane < 16);
                sink.push(lane);
            }
            Instruction::I8x16ExtractLaneU(lane) => {
                sink.push(0xFD);
                0x16u32.encode(sink);
                assert!(lane < 16);
                sink.push(lane);
            }
            Instruction::I8x16ReplaceLane(lane) => {
                sink.push(0xFD);
                0x17u32.encode(sink);
                assert!(lane < 16);
                sink.push(lane);
            }
            Instruction::I16x8ExtractLaneS(lane) => {
                sink.push(0xFD);
                0x18u32.encode(sink);
                assert!(lane < 8);
                sink.push(lane);
            }
            Instruction::I16x8ExtractLaneU(lane) => {
                sink.push(0xFD);
                0x19u32.encode(sink);
                assert!(lane < 8);
                sink.push(lane);
            }
            Instruction::I16x8ReplaceLane(lane) => {
                sink.push(0xFD);
                0x1Au32.encode(sink);
                assert!(lane < 8);
                sink.push(lane);
            }
            Instruction::I32x4ExtractLane(lane) => {
                sink.push(0xFD);
                0x1Bu32.encode(sink);
                assert!(lane < 4);
                sink.push(lane);
            }
            Instruction::I32x4ReplaceLane(lane) => {
                sink.push(0xFD);
                0x1Cu32.encode(sink);
                assert!(lane < 4);
                sink.push(lane);
            }
            Instruction::I64x2ExtractLane(lane) => {
                sink.push(0xFD);
                0x1Du32.encode(sink);
                assert!(lane < 2);
                sink.push(lane);
            }
            Instruction::I64x2ReplaceLane(lane) => {
                sink.push(0xFD);
                0x1Eu32.encode(sink);
                assert!(lane < 2);
                sink.push(lane);
            }
            Instruction::F32x4ExtractLane(lane) => {
                sink.push(0xFD);
                0x1Fu32.encode(sink);
                assert!(lane < 4);
                sink.push(lane);
            }
            Instruction::F32x4ReplaceLane(lane) => {
                sink.push(0xFD);
                0x20u32.encode(sink);
                assert!(lane < 4);
                sink.push(lane);
            }
            Instruction::F64x2ExtractLane(lane) => {
                sink.push(0xFD);
                0x21u32.encode(sink);
                assert!(lane < 2);
                sink.push(lane);
            }
            Instruction::F64x2ReplaceLane(lane) => {
                sink.push(0xFD);
                0x22u32.encode(sink);
                assert!(lane < 2);
                sink.push(lane);
            }

            Instruction::I8x16Eq => {
                sink.push(0xFD);
                0x23u32.encode(sink);
            }
            Instruction::I8x16Ne => {
                sink.push(0xFD);
                0x24u32.encode(sink);
            }
            Instruction::I8x16LtS => {
                sink.push(0xFD);
                0x25u32.encode(sink);
            }
            Instruction::I8x16LtU => {
                sink.push(0xFD);
                0x26u32.encode(sink);
            }
            Instruction::I8x16GtS => {
                sink.push(0xFD);
                0x27u32.encode(sink);
            }
            Instruction::I8x16GtU => {
                sink.push(0xFD);
                0x28u32.encode(sink);
            }
            Instruction::I8x16LeS => {
                sink.push(0xFD);
                0x29u32.encode(sink);
            }
            Instruction::I8x16LeU => {
                sink.push(0xFD);
                0x2Au32.encode(sink);
            }
            Instruction::I8x16GeS => {
                sink.push(0xFD);
                0x2Bu32.encode(sink);
            }
            Instruction::I8x16GeU => {
                sink.push(0xFD);
                0x2Cu32.encode(sink);
            }
            Instruction::I16x8Eq => {
                sink.push(0xFD);
                0x2Du32.encode(sink);
            }
            Instruction::I16x8Ne => {
                sink.push(0xFD);
                0x2Eu32.encode(sink);
            }
            Instruction::I16x8LtS => {
                sink.push(0xFD);
                0x2Fu32.encode(sink);
            }
            Instruction::I16x8LtU => {
                sink.push(0xFD);
                0x30u32.encode(sink);
            }
            Instruction::I16x8GtS => {
                sink.push(0xFD);
                0x31u32.encode(sink);
            }
            Instruction::I16x8GtU => {
                sink.push(0xFD);
                0x32u32.encode(sink);
            }
            Instruction::I16x8LeS => {
                sink.push(0xFD);
                0x33u32.encode(sink);
            }
            Instruction::I16x8LeU => {
                sink.push(0xFD);
                0x34u32.encode(sink);
            }
            Instruction::I16x8GeS => {
                sink.push(0xFD);
                0x35u32.encode(sink);
            }
            Instruction::I16x8GeU => {
                sink.push(0xFD);
                0x36u32.encode(sink);
            }
            Instruction::I32x4Eq => {
                sink.push(0xFD);
                0x37u32.encode(sink);
            }
            Instruction::I32x4Ne => {
                sink.push(0xFD);
                0x38u32.encode(sink);
            }
            Instruction::I32x4LtS => {
                sink.push(0xFD);
                0x39u32.encode(sink);
            }
            Instruction::I32x4LtU => {
                sink.push(0xFD);
                0x3Au32.encode(sink);
            }
            Instruction::I32x4GtS => {
                sink.push(0xFD);
                0x3Bu32.encode(sink);
            }
            Instruction::I32x4GtU => {
                sink.push(0xFD);
                0x3Cu32.encode(sink);
            }
            Instruction::I32x4LeS => {
                sink.push(0xFD);
                0x3Du32.encode(sink);
            }
            Instruction::I32x4LeU => {
                sink.push(0xFD);
                0x3Eu32.encode(sink);
            }
            Instruction::I32x4GeS => {
                sink.push(0xFD);
                0x3Fu32.encode(sink);
            }
            Instruction::I32x4GeU => {
                sink.push(0xFD);
                0x40u32.encode(sink);
            }
            Instruction::F32x4Eq => {
                sink.push(0xFD);
                0x41u32.encode(sink);
            }
            Instruction::F32x4Ne => {
                sink.push(0xFD);
                0x42u32.encode(sink);
            }
            Instruction::F32x4Lt => {
                sink.push(0xFD);
                0x43u32.encode(sink);
            }
            Instruction::F32x4Gt => {
                sink.push(0xFD);
                0x44u32.encode(sink);
            }
            Instruction::F32x4Le => {
                sink.push(0xFD);
                0x45u32.encode(sink);
            }
            Instruction::F32x4Ge => {
                sink.push(0xFD);
                0x46u32.encode(sink);
            }
            Instruction::F64x2Eq => {
                sink.push(0xFD);
                0x47u32.encode(sink);
            }
            Instruction::F64x2Ne => {
                sink.push(0xFD);
                0x48u32.encode(sink);
            }
            Instruction::F64x2Lt => {
                sink.push(0xFD);
                0x49u32.encode(sink);
            }
            Instruction::F64x2Gt => {
                sink.push(0xFD);
                0x4Au32.encode(sink);
            }
            Instruction::F64x2Le => {
                sink.push(0xFD);
                0x4Bu32.encode(sink);
            }
            Instruction::F64x2Ge => {
                sink.push(0xFD);
                0x4Cu32.encode(sink);
            }
            Instruction::V128Not => {
                sink.push(0xFD);
                0x4Du32.encode(sink);
            }
            Instruction::V128And => {
                sink.push(0xFD);
                0x4Eu32.encode(sink);
            }
            Instruction::V128AndNot => {
                sink.push(0xFD);
                0x4Fu32.encode(sink);
            }
            Instruction::V128Or => {
                sink.push(0xFD);
                0x50u32.encode(sink);
            }
            Instruction::V128Xor => {
                sink.push(0xFD);
                0x51u32.encode(sink);
            }
            Instruction::V128Bitselect => {
                sink.push(0xFD);
                0x52u32.encode(sink);
            }
            Instruction::V128AnyTrue => {
                sink.push(0xFD);
                0x53u32.encode(sink);
            }
            Instruction::I8x16Abs => {
                sink.push(0xFD);
                0x60u32.encode(sink);
            }
            Instruction::I8x16Neg => {
                sink.push(0xFD);
                0x61u32.encode(sink);
            }
            Instruction::I8x16Popcnt => {
                sink.push(0xFD);
                0x62u32.encode(sink);
            }
            Instruction::I8x16AllTrue => {
                sink.push(0xFD);
                0x63u32.encode(sink);
            }
            Instruction::I8x16Bitmask => {
                sink.push(0xFD);
                0x64u32.encode(sink);
            }
            Instruction::I8x16NarrowI16x8S => {
                sink.push(0xFD);
                0x65u32.encode(sink);
            }
            Instruction::I8x16NarrowI16x8U => {
                sink.push(0xFD);
                0x66u32.encode(sink);
            }
            Instruction::I8x16Shl => {
                sink.push(0xFD);
                0x6bu32.encode(sink);
            }
            Instruction::I8x16ShrS => {
                sink.push(0xFD);
                0x6cu32.encode(sink);
            }
            Instruction::I8x16ShrU => {
                sink.push(0xFD);
                0x6du32.encode(sink);
            }
            Instruction::I8x16Add => {
                sink.push(0xFD);
                0x6eu32.encode(sink);
            }
            Instruction::I8x16AddSatS => {
                sink.push(0xFD);
                0x6fu32.encode(sink);
            }
            Instruction::I8x16AddSatU => {
                sink.push(0xFD);
                0x70u32.encode(sink);
            }
            Instruction::I8x16Sub => {
                sink.push(0xFD);
                0x71u32.encode(sink);
            }
            Instruction::I8x16SubSatS => {
                sink.push(0xFD);
                0x72u32.encode(sink);
            }
            Instruction::I8x16SubSatU => {
                sink.push(0xFD);
                0x73u32.encode(sink);
            }
            Instruction::I8x16MinS => {
                sink.push(0xFD);
                0x76u32.encode(sink);
            }
            Instruction::I8x16MinU => {
                sink.push(0xFD);
                0x77u32.encode(sink);
            }
            Instruction::I8x16MaxS => {
                sink.push(0xFD);
                0x78u32.encode(sink);
            }
            Instruction::I8x16MaxU => {
                sink.push(0xFD);
                0x79u32.encode(sink);
            }
            Instruction::I8x16AvgrU => {
                sink.push(0xFD);
                0x7Bu32.encode(sink);
            }
            Instruction::I16x8ExtAddPairwiseI8x16S => {
                sink.push(0xFD);
                0x7Cu32.encode(sink);
            }
            Instruction::I16x8ExtAddPairwiseI8x16U => {
                sink.push(0xFD);
                0x7Du32.encode(sink);
            }
            Instruction::I32x4ExtAddPairwiseI16x8S => {
                sink.push(0xFD);
                0x7Eu32.encode(sink);
            }
            Instruction::I32x4ExtAddPairwiseI16x8U => {
                sink.push(0xFD);
                0x7Fu32.encode(sink);
            }
            Instruction::I16x8Abs => {
                sink.push(0xFD);
                0x80u32.encode(sink);
            }
            Instruction::I16x8Neg => {
                sink.push(0xFD);
                0x81u32.encode(sink);
            }
            Instruction::I16x8Q15MulrSatS => {
                sink.push(0xFD);
                0x82u32.encode(sink);
            }
            Instruction::I16x8AllTrue => {
                sink.push(0xFD);
                0x83u32.encode(sink);
            }
            Instruction::I16x8Bitmask => {
                sink.push(0xFD);
                0x84u32.encode(sink);
            }
            Instruction::I16x8NarrowI32x4S => {
                sink.push(0xFD);
                0x85u32.encode(sink);
            }
            Instruction::I16x8NarrowI32x4U => {
                sink.push(0xFD);
                0x86u32.encode(sink);
            }
            Instruction::I16x8ExtendLowI8x16S => {
                sink.push(0xFD);
                0x87u32.encode(sink);
            }
            Instruction::I16x8ExtendHighI8x16S => {
                sink.push(0xFD);
                0x88u32.encode(sink);
            }
            Instruction::I16x8ExtendLowI8x16U => {
                sink.push(0xFD);
                0x89u32.encode(sink);
            }
            Instruction::I16x8ExtendHighI8x16U => {
                sink.push(0xFD);
                0x8Au32.encode(sink);
            }
            Instruction::I16x8Shl => {
                sink.push(0xFD);
                0x8Bu32.encode(sink);
            }
            Instruction::I16x8ShrS => {
                sink.push(0xFD);
                0x8Cu32.encode(sink);
            }
            Instruction::I16x8ShrU => {
                sink.push(0xFD);
                0x8Du32.encode(sink);
            }
            Instruction::I16x8Add => {
                sink.push(0xFD);
                0x8Eu32.encode(sink);
            }
            Instruction::I16x8AddSatS => {
                sink.push(0xFD);
                0x8Fu32.encode(sink);
            }
            Instruction::I16x8AddSatU => {
                sink.push(0xFD);
                0x90u32.encode(sink);
            }
            Instruction::I16x8Sub => {
                sink.push(0xFD);
                0x91u32.encode(sink);
            }
            Instruction::I16x8SubSatS => {
                sink.push(0xFD);
                0x92u32.encode(sink);
            }
            Instruction::I16x8SubSatU => {
                sink.push(0xFD);
                0x93u32.encode(sink);
            }
            Instruction::I16x8Mul => {
                sink.push(0xFD);
                0x95u32.encode(sink);
            }
            Instruction::I16x8MinS => {
                sink.push(0xFD);
                0x96u32.encode(sink);
            }
            Instruction::I16x8MinU => {
                sink.push(0xFD);
                0x97u32.encode(sink);
            }
            Instruction::I16x8MaxS => {
                sink.push(0xFD);
                0x98u32.encode(sink);
            }
            Instruction::I16x8MaxU => {
                sink.push(0xFD);
                0x99u32.encode(sink);
            }
            Instruction::I16x8AvgrU => {
                sink.push(0xFD);
                0x9Bu32.encode(sink);
            }
            Instruction::I16x8ExtMulLowI8x16S => {
                sink.push(0xFD);
                0x9Cu32.encode(sink);
            }
            Instruction::I16x8ExtMulHighI8x16S => {
                sink.push(0xFD);
                0x9Du32.encode(sink);
            }
            Instruction::I16x8ExtMulLowI8x16U => {
                sink.push(0xFD);
                0x9Eu32.encode(sink);
            }
            Instruction::I16x8ExtMulHighI8x16U => {
                sink.push(0xFD);
                0x9Fu32.encode(sink);
            }
            Instruction::I32x4Abs => {
                sink.push(0xFD);
                0xA0u32.encode(sink);
            }
            Instruction::I32x4Neg => {
                sink.push(0xFD);
                0xA1u32.encode(sink);
            }
            Instruction::I32x4AllTrue => {
                sink.push(0xFD);
                0xA3u32.encode(sink);
            }
            Instruction::I32x4Bitmask => {
                sink.push(0xFD);
                0xA4u32.encode(sink);
            }
            Instruction::I32x4ExtendLowI16x8S => {
                sink.push(0xFD);
                0xA7u32.encode(sink);
            }
            Instruction::I32x4ExtendHighI16x8S => {
                sink.push(0xFD);
                0xA8u32.encode(sink);
            }
            Instruction::I32x4ExtendLowI16x8U => {
                sink.push(0xFD);
                0xA9u32.encode(sink);
            }
            Instruction::I32x4ExtendHighI16x8U => {
                sink.push(0xFD);
                0xAAu32.encode(sink);
            }
            Instruction::I32x4Shl => {
                sink.push(0xFD);
                0xABu32.encode(sink);
            }
            Instruction::I32x4ShrS => {
                sink.push(0xFD);
                0xACu32.encode(sink);
            }
            Instruction::I32x4ShrU => {
                sink.push(0xFD);
                0xADu32.encode(sink);
            }
            Instruction::I32x4Add => {
                sink.push(0xFD);
                0xAEu32.encode(sink);
            }
            Instruction::I32x4Sub => {
                sink.push(0xFD);
                0xB1u32.encode(sink);
            }
            Instruction::I32x4Mul => {
                sink.push(0xFD);
                0xB5u32.encode(sink);
            }
            Instruction::I32x4MinS => {
                sink.push(0xFD);
                0xB6u32.encode(sink);
            }
            Instruction::I32x4MinU => {
                sink.push(0xFD);
                0xB7u32.encode(sink);
            }
            Instruction::I32x4MaxS => {
                sink.push(0xFD);
                0xB8u32.encode(sink);
            }
            Instruction::I32x4MaxU => {
                sink.push(0xFD);
                0xB9u32.encode(sink);
            }
            Instruction::I32x4DotI16x8S => {
                sink.push(0xFD);
                0xBAu32.encode(sink);
            }
            Instruction::I32x4ExtMulLowI16x8S => {
                sink.push(0xFD);
                0xBCu32.encode(sink);
            }
            Instruction::I32x4ExtMulHighI16x8S => {
                sink.push(0xFD);
                0xBDu32.encode(sink);
            }
            Instruction::I32x4ExtMulLowI16x8U => {
                sink.push(0xFD);
                0xBEu32.encode(sink);
            }
            Instruction::I32x4ExtMulHighI16x8U => {
                sink.push(0xFD);
                0xBFu32.encode(sink);
            }
            Instruction::I64x2Abs => {
                sink.push(0xFD);
                0xC0u32.encode(sink);
            }
            Instruction::I64x2Neg => {
                sink.push(0xFD);
                0xC1u32.encode(sink);
            }
            Instruction::I64x2AllTrue => {
                sink.push(0xFD);
                0xC3u32.encode(sink);
            }
            Instruction::I64x2Bitmask => {
                sink.push(0xFD);
                0xC4u32.encode(sink);
            }
            Instruction::I64x2ExtendLowI32x4S => {
                sink.push(0xFD);
                0xC7u32.encode(sink);
            }
            Instruction::I64x2ExtendHighI32x4S => {
                sink.push(0xFD);
                0xC8u32.encode(sink);
            }
            Instruction::I64x2ExtendLowI32x4U => {
                sink.push(0xFD);
                0xC9u32.encode(sink);
            }
            Instruction::I64x2ExtendHighI32x4U => {
                sink.push(0xFD);
                0xCAu32.encode(sink);
            }
            Instruction::I64x2Shl => {
                sink.push(0xFD);
                0xCBu32.encode(sink);
            }
            Instruction::I64x2ShrS => {
                sink.push(0xFD);
                0xCCu32.encode(sink);
            }
            Instruction::I64x2ShrU => {
                sink.push(0xFD);
                0xCDu32.encode(sink);
            }
            Instruction::I64x2Add => {
                sink.push(0xFD);
                0xCEu32.encode(sink);
            }
            Instruction::I64x2Sub => {
                sink.push(0xFD);
                0xD1u32.encode(sink);
            }
            Instruction::I64x2Mul => {
                sink.push(0xFD);
                0xD5u32.encode(sink);
            }
            Instruction::I64x2ExtMulLowI32x4S => {
                sink.push(0xFD);
                0xDCu32.encode(sink);
            }
            Instruction::I64x2ExtMulHighI32x4S => {
                sink.push(0xFD);
                0xDDu32.encode(sink);
            }
            Instruction::I64x2ExtMulLowI32x4U => {
                sink.push(0xFD);
                0xDEu32.encode(sink);
            }
            Instruction::I64x2ExtMulHighI32x4U => {
                sink.push(0xFD);
                0xDFu32.encode(sink);
            }
            Instruction::F32x4Ceil => {
                sink.push(0xFD);
                0x67u32.encode(sink);
            }
            Instruction::F32x4Floor => {
                sink.push(0xFD);
                0x68u32.encode(sink);
            }
            Instruction::F32x4Trunc => {
                sink.push(0xFD);
                0x69u32.encode(sink);
            }
            Instruction::F32x4Nearest => {
                sink.push(0xFD);
                0x6Au32.encode(sink);
            }
            Instruction::F32x4Abs => {
                sink.push(0xFD);
                0xE0u32.encode(sink);
            }
            Instruction::F32x4Neg => {
                sink.push(0xFD);
                0xE1u32.encode(sink);
            }
            Instruction::F32x4Sqrt => {
                sink.push(0xFD);
                0xE3u32.encode(sink);
            }
            Instruction::F32x4Add => {
                sink.push(0xFD);
                0xE4u32.encode(sink);
            }
            Instruction::F32x4Sub => {
                sink.push(0xFD);
                0xE5u32.encode(sink);
            }
            Instruction::F32x4Mul => {
                sink.push(0xFD);
                0xE6u32.encode(sink);
            }
            Instruction::F32x4Div => {
                sink.push(0xFD);
                0xE7u32.encode(sink);
            }
            Instruction::F32x4Min => {
                sink.push(0xFD);
                0xE8u32.encode(sink);
            }
            Instruction::F32x4Max => {
                sink.push(0xFD);
                0xE9u32.encode(sink);
            }
            Instruction::F32x4PMin => {
                sink.push(0xFD);
                0xEAu32.encode(sink);
            }
            Instruction::F32x4PMax => {
                sink.push(0xFD);
                0xEBu32.encode(sink);
            }
            Instruction::F64x2Ceil => {
                sink.push(0xFD);
                0x74u32.encode(sink);
            }
            Instruction::F64x2Floor => {
                sink.push(0xFD);
                0x75u32.encode(sink);
            }
            Instruction::F64x2Trunc => {
                sink.push(0xFD);
                0x7Au32.encode(sink);
            }
            Instruction::F64x2Nearest => {
                sink.push(0xFD);
                0x94u32.encode(sink);
            }
            Instruction::F64x2Abs => {
                sink.push(0xFD);
                0xECu32.encode(sink);
            }
            Instruction::F64x2Neg => {
                sink.push(0xFD);
                0xEDu32.encode(sink);
            }
            Instruction::F64x2Sqrt => {
                sink.push(0xFD);
                0xEFu32.encode(sink);
            }
            Instruction::F64x2Add => {
                sink.push(0xFD);
                0xF0u32.encode(sink);
            }
            Instruction::F64x2Sub => {
                sink.push(0xFD);
                0xF1u32.encode(sink);
            }
            Instruction::F64x2Mul => {
                sink.push(0xFD);
                0xF2u32.encode(sink);
            }
            Instruction::F64x2Div => {
                sink.push(0xFD);
                0xF3u32.encode(sink);
            }
            Instruction::F64x2Min => {
                sink.push(0xFD);
                0xF4u32.encode(sink);
            }
            Instruction::F64x2Max => {
                sink.push(0xFD);
                0xF5u32.encode(sink);
            }
            Instruction::F64x2PMin => {
                sink.push(0xFD);
                0xF6u32.encode(sink);
            }
            Instruction::F64x2PMax => {
                sink.push(0xFD);
                0xF7u32.encode(sink);
            }
            Instruction::I32x4TruncSatF32x4S => {
                sink.push(0xFD);
                0xF8u32.encode(sink);
            }
            Instruction::I32x4TruncSatF32x4U => {
                sink.push(0xFD);
                0xF9u32.encode(sink);
            }
            Instruction::F32x4ConvertI32x4S => {
                sink.push(0xFD);
                0xFAu32.encode(sink);
            }
            Instruction::F32x4ConvertI32x4U => {
                sink.push(0xFD);
                0xFBu32.encode(sink);
            }
            Instruction::I32x4TruncSatF64x2SZero => {
                sink.push(0xFD);
                0xFCu32.encode(sink);
            }
            Instruction::I32x4TruncSatF64x2UZero => {
                sink.push(0xFD);
                0xFDu32.encode(sink);
            }
            Instruction::F64x2ConvertLowI32x4S => {
                sink.push(0xFD);
                0xFEu32.encode(sink);
            }
            Instruction::F64x2ConvertLowI32x4U => {
                sink.push(0xFD);
                0xFFu32.encode(sink);
            }
            Instruction::F32x4DemoteF64x2Zero => {
                sink.push(0xFD);
                0x5Eu32.encode(sink);
            }
            Instruction::F64x2PromoteLowF32x4 => {
                sink.push(0xFD);
                0x5Fu32.encode(sink);
            }
            Instruction::V128Load32Zero(memarg) => {
                sink.push(0xFD);
                0x5Cu32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load64Zero(memarg) => {
                sink.push(0xFD);
                0x5Du32.encode(sink);
                memarg.encode(sink);
            }
            Instruction::V128Load8Lane { memarg, lane } => {
                sink.push(0xFD);
                0x54u32.encode(sink);
                memarg.encode(sink);
                assert!(lane < 16);
                sink.push(lane);
            }
            Instruction::V128Load16Lane { memarg, lane } => {
                sink.push(0xFD);
                0x55u32.encode(sink);
                memarg.encode(sink);
                assert!(lane < 8);
                sink.push(lane);
            }
            Instruction::V128Load32Lane { memarg, lane } => {
                sink.push(0xFD);
                0x56u32.encode(sink);
                memarg.encode(sink);
                assert!(lane < 4);
                sink.push(lane);
            }
            Instruction::V128Load64Lane { memarg, lane } => {
                sink.push(0xFD);
                0x57u32.encode(sink);
                memarg.encode(sink);
                assert!(lane < 2);
                sink.push(lane);
            }
            Instruction::V128Store8Lane { memarg, lane } => {
                sink.push(0xFD);
                0x58u32.encode(sink);
                memarg.encode(sink);
                assert!(lane < 16);
                sink.push(lane);
            }
            Instruction::V128Store16Lane { memarg, lane } => {
                sink.push(0xFD);
                0x59u32.encode(sink);
                memarg.encode(sink);
                assert!(lane < 8);
                sink.push(lane);
            }
            Instruction::V128Store32Lane { memarg, lane } => {
                sink.push(0xFD);
                0x5Au32.encode(sink);
                memarg.encode(sink);
                assert!(lane < 4);
                sink.push(lane);
            }
            Instruction::V128Store64Lane { memarg, lane } => {
                sink.push(0xFD);
                0x5Bu32.encode(sink);
                memarg.encode(sink);
                assert!(lane < 2);
                sink.push(lane);
            }
            Instruction::I64x2Eq => {
                sink.push(0xFD);
                0xD6u32.encode(sink);
            }
            Instruction::I64x2Ne => {
                sink.push(0xFD);
                0xD7u32.encode(sink);
            }
            Instruction::I64x2LtS => {
                sink.push(0xFD);
                0xD8u32.encode(sink);
            }
            Instruction::I64x2GtS => {
                sink.push(0xFD);
                0xD9u32.encode(sink);
            }
            Instruction::I64x2LeS => {
                sink.push(0xFD);
                0xDAu32.encode(sink);
            }
            Instruction::I64x2GeS => {
                sink.push(0xFD);
                0xDBu32.encode(sink);
            }
            Instruction::I8x16RelaxedSwizzle => {
                sink.push(0xFD);
                0x100u32.encode(sink);
            }
            Instruction::I32x4RelaxedTruncF32x4S => {
                sink.push(0xFD);
                0x101u32.encode(sink);
            }
            Instruction::I32x4RelaxedTruncF32x4U => {
                sink.push(0xFD);
                0x102u32.encode(sink);
            }
            Instruction::I32x4RelaxedTruncF64x2SZero => {
                sink.push(0xFD);
                0x103u32.encode(sink);
            }
            Instruction::I32x4RelaxedTruncF64x2UZero => {
                sink.push(0xFD);
                0x104u32.encode(sink);
            }
            Instruction::F32x4RelaxedMadd => {
                sink.push(0xFD);
                0x105u32.encode(sink);
            }
            Instruction::F32x4RelaxedNmadd => {
                sink.push(0xFD);
                0x106u32.encode(sink);
            }
            Instruction::F64x2RelaxedMadd => {
                sink.push(0xFD);
                0x107u32.encode(sink);
            }
            Instruction::F64x2RelaxedNmadd => {
                sink.push(0xFD);
                0x108u32.encode(sink);
            }
            Instruction::I8x16RelaxedLaneselect => {
                sink.push(0xFD);
                0x109u32.encode(sink);
            }
            Instruction::I16x8RelaxedLaneselect => {
                sink.push(0xFD);
                0x10Au32.encode(sink);
            }
            Instruction::I32x4RelaxedLaneselect => {
                sink.push(0xFD);
                0x10Bu32.encode(sink);
            }
            Instruction::I64x2RelaxedLaneselect => {
                sink.push(0xFD);
                0x10Cu32.encode(sink);
            }
            Instruction::F32x4RelaxedMin => {
                sink.push(0xFD);
                0x10Du32.encode(sink);
            }
            Instruction::F32x4RelaxedMax => {
                sink.push(0xFD);
                0x10Eu32.encode(sink);
            }
            Instruction::F64x2RelaxedMin => {
                sink.push(0xFD);
                0x10Fu32.encode(sink);
            }
            Instruction::F64x2RelaxedMax => {
                sink.push(0xFD);
                0x110u32.encode(sink);
            }
            Instruction::I16x8RelaxedQ15mulrS => {
                sink.push(0xFD);
                0x111u32.encode(sink);
            }
            Instruction::I16x8RelaxedDotI8x16I7x16S => {
                sink.push(0xFD);
                0x112u32.encode(sink);
            }
            Instruction::I32x4RelaxedDotI8x16I7x16AddS => {
                sink.push(0xFD);
                0x113u32.encode(sink);
            }

            // Atomic instructions from the thread proposal
            Instruction::MemoryAtomicNotify(memarg) => {
                sink.push(0xFE);
                sink.push(0x00);
                memarg.encode(sink);
            }
            Instruction::MemoryAtomicWait32(memarg) => {
                sink.push(0xFE);
                sink.push(0x01);
                memarg.encode(sink);
            }
            Instruction::MemoryAtomicWait64(memarg) => {
                sink.push(0xFE);
                sink.push(0x02);
                memarg.encode(sink);
            }
            Instruction::AtomicFence => {
                sink.push(0xFE);
                sink.push(0x03);
                sink.push(0x00);
            }
            Instruction::I32AtomicLoad(memarg) => {
                sink.push(0xFE);
                sink.push(0x10);
                memarg.encode(sink);
            }
            Instruction::I64AtomicLoad(memarg) => {
                sink.push(0xFE);
                sink.push(0x11);
                memarg.encode(sink);
            }
            Instruction::I32AtomicLoad8U(memarg) => {
                sink.push(0xFE);
                sink.push(0x12);
                memarg.encode(sink);
            }
            Instruction::I32AtomicLoad16U(memarg) => {
                sink.push(0xFE);
                sink.push(0x13);
                memarg.encode(sink);
            }
            Instruction::I64AtomicLoad8U(memarg) => {
                sink.push(0xFE);
                sink.push(0x14);
                memarg.encode(sink);
            }
            Instruction::I64AtomicLoad16U(memarg) => {
                sink.push(0xFE);
                sink.push(0x15);
                memarg.encode(sink);
            }
            Instruction::I64AtomicLoad32U(memarg) => {
                sink.push(0xFE);
                sink.push(0x16);
                memarg.encode(sink);
            }
            Instruction::I32AtomicStore(memarg) => {
                sink.push(0xFE);
                sink.push(0x17);
                memarg.encode(sink);
            }
            Instruction::I64AtomicStore(memarg) => {
                sink.push(0xFE);
                sink.push(0x18);
                memarg.encode(sink);
            }
            Instruction::I32AtomicStore8(memarg) => {
                sink.push(0xFE);
                sink.push(0x19);
                memarg.encode(sink);
            }
            Instruction::I32AtomicStore16(memarg) => {
                sink.push(0xFE);
                sink.push(0x1A);
                memarg.encode(sink);
            }
            Instruction::I64AtomicStore8(memarg) => {
                sink.push(0xFE);
                sink.push(0x1B);
                memarg.encode(sink);
            }
            Instruction::I64AtomicStore16(memarg) => {
                sink.push(0xFE);
                sink.push(0x1C);
                memarg.encode(sink);
            }
            Instruction::I64AtomicStore32(memarg) => {
                sink.push(0xFE);
                sink.push(0x1D);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmwAdd(memarg) => {
                sink.push(0xFE);
                sink.push(0x1E);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmwAdd(memarg) => {
                sink.push(0xFE);
                sink.push(0x1F);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw8AddU(memarg) => {
                sink.push(0xFE);
                sink.push(0x20);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw16AddU(memarg) => {
                sink.push(0xFE);
                sink.push(0x21);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw8AddU(memarg) => {
                sink.push(0xFE);
                sink.push(0x22);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw16AddU(memarg) => {
                sink.push(0xFE);
                sink.push(0x23);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw32AddU(memarg) => {
                sink.push(0xFE);
                sink.push(0x24);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmwSub(memarg) => {
                sink.push(0xFE);
                sink.push(0x25);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmwSub(memarg) => {
                sink.push(0xFE);
                sink.push(0x26);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw8SubU(memarg) => {
                sink.push(0xFE);
                sink.push(0x27);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw16SubU(memarg) => {
                sink.push(0xFE);
                sink.push(0x28);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw8SubU(memarg) => {
                sink.push(0xFE);
                sink.push(0x29);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw16SubU(memarg) => {
                sink.push(0xFE);
                sink.push(0x2A);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw32SubU(memarg) => {
                sink.push(0xFE);
                sink.push(0x2B);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmwAnd(memarg) => {
                sink.push(0xFE);
                sink.push(0x2C);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmwAnd(memarg) => {
                sink.push(0xFE);
                sink.push(0x2D);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw8AndU(memarg) => {
                sink.push(0xFE);
                sink.push(0x2E);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw16AndU(memarg) => {
                sink.push(0xFE);
                sink.push(0x2F);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw8AndU(memarg) => {
                sink.push(0xFE);
                sink.push(0x30);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw16AndU(memarg) => {
                sink.push(0xFE);
                sink.push(0x31);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw32AndU(memarg) => {
                sink.push(0xFE);
                sink.push(0x32);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmwOr(memarg) => {
                sink.push(0xFE);
                sink.push(0x33);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmwOr(memarg) => {
                sink.push(0xFE);
                sink.push(0x34);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw8OrU(memarg) => {
                sink.push(0xFE);
                sink.push(0x35);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw16OrU(memarg) => {
                sink.push(0xFE);
                sink.push(0x36);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw8OrU(memarg) => {
                sink.push(0xFE);
                sink.push(0x37);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw16OrU(memarg) => {
                sink.push(0xFE);
                sink.push(0x38);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw32OrU(memarg) => {
                sink.push(0xFE);
                sink.push(0x39);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmwXor(memarg) => {
                sink.push(0xFE);
                sink.push(0x3A);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmwXor(memarg) => {
                sink.push(0xFE);
                sink.push(0x3B);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw8XorU(memarg) => {
                sink.push(0xFE);
                sink.push(0x3C);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw16XorU(memarg) => {
                sink.push(0xFE);
                sink.push(0x3D);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw8XorU(memarg) => {
                sink.push(0xFE);
                sink.push(0x3E);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw16XorU(memarg) => {
                sink.push(0xFE);
                sink.push(0x3F);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw32XorU(memarg) => {
                sink.push(0xFE);
                sink.push(0x40);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmwXchg(memarg) => {
                sink.push(0xFE);
                sink.push(0x41);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmwXchg(memarg) => {
                sink.push(0xFE);
                sink.push(0x42);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw8XchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x43);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw16XchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x44);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw8XchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x45);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw16XchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x46);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw32XchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x47);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmwCmpxchg(memarg) => {
                sink.push(0xFE);
                sink.push(0x48);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmwCmpxchg(memarg) => {
                sink.push(0xFE);
                sink.push(0x49);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw8CmpxchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x4A);
                memarg.encode(sink);
            }
            Instruction::I32AtomicRmw16CmpxchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x4B);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw8CmpxchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x4C);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw16CmpxchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x4D);
                memarg.encode(sink);
            }
            Instruction::I64AtomicRmw32CmpxchgU(memarg) => {
                sink.push(0xFE);
                sink.push(0x4E);
                memarg.encode(sink);
            }

            // Atomic instructions from the shared-everything-threads proposal
            Instruction::GlobalAtomicGet {
                ordering,
                global_index,
            } => {
                sink.push(0xFE);
                sink.push(0x4F);
                ordering.encode(sink);
                global_index.encode(sink);
            }
            Instruction::GlobalAtomicSet {
                ordering,
                global_index,
            } => {
                sink.push(0xFE);
                sink.push(0x50);
                ordering.encode(sink);
                global_index.encode(sink);
            }
            Instruction::GlobalAtomicRmwAdd {
                ordering,
                global_index,
            } => {
                sink.push(0xFE);
                sink.push(0x51);
                ordering.encode(sink);
                global_index.encode(sink);
            }
            Instruction::GlobalAtomicRmwSub {
                ordering,
                global_index,
            } => {
                sink.push(0xFE);
                sink.push(0x52);
                ordering.encode(sink);
                global_index.encode(sink);
            }
            Instruction::GlobalAtomicRmwAnd {
                ordering,
                global_index,
            } => {
                sink.push(0xFE);
                sink.push(0x53);
                ordering.encode(sink);
                global_index.encode(sink);
            }
            Instruction::GlobalAtomicRmwOr {
                ordering,
                global_index,
            } => {
                sink.push(0xFE);
                sink.push(0x54);
                ordering.encode(sink);
                global_index.encode(sink);
            }
            Instruction::GlobalAtomicRmwXor {
                ordering,
                global_index,
            } => {
                sink.push(0xFE);
                sink.push(0x55);
                ordering.encode(sink);
                global_index.encode(sink);
            }
            Instruction::GlobalAtomicRmwXchg {
                ordering,
                global_index,
            } => {
                sink.push(0xFE);
                sink.push(0x56);
                ordering.encode(sink);
                global_index.encode(sink);
            }
            Instruction::GlobalAtomicRmwCmpxchg {
                ordering,
                global_index,
            } => {
                sink.push(0xFE);
                sink.push(0x57);
                ordering.encode(sink);
                global_index.encode(sink);
            }
        }
    }
}

#[derive(Clone, Debug)]
#[allow(missing_docs)]
pub enum Catch {
    One { tag: u32, label: u32 },
    OneRef { tag: u32, label: u32 },
    All { label: u32 },
    AllRef { label: u32 },
}

impl Encode for Catch {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            Catch::One { tag, label } => {
                sink.push(0x00);
                tag.encode(sink);
                label.encode(sink);
            }
            Catch::OneRef { tag, label } => {
                sink.push(0x01);
                tag.encode(sink);
                label.encode(sink);
            }
            Catch::All { label } => {
                sink.push(0x02);
                label.encode(sink);
            }
            Catch::AllRef { label } => {
                sink.push(0x03);
                label.encode(sink);
            }
        }
    }
}

/// A constant expression.
///
/// Usable in contexts such as offsets or initializers.
#[derive(Debug)]
pub struct ConstExpr {
    bytes: Vec<u8>,
}

impl ConstExpr {
    /// Create a new empty constant expression builder.
    pub fn empty() -> Self {
        Self { bytes: Vec::new() }
    }

    /// Create a constant expression with the specified raw encoding of instructions.
    pub fn raw(bytes: impl IntoIterator<Item = u8>) -> Self {
        Self {
            bytes: bytes.into_iter().collect(),
        }
    }

    fn new_insn(insn: Instruction) -> Self {
        let mut bytes = vec![];
        insn.encode(&mut bytes);
        Self { bytes }
    }

    fn with_insn(mut self, insn: Instruction) -> Self {
        insn.encode(&mut self.bytes);
        self
    }

    /// Create a constant expression containing a single `global.get` instruction.
    pub fn global_get(index: u32) -> Self {
        Self::new_insn(Instruction::GlobalGet(index))
    }

    /// Create a constant expression containing a single `ref.null` instruction.
    pub fn ref_null(ty: HeapType) -> Self {
        Self::new_insn(Instruction::RefNull(ty))
    }

    /// Create a constant expression containing a single `ref.func` instruction.
    pub fn ref_func(func: u32) -> Self {
        Self::new_insn(Instruction::RefFunc(func))
    }

    /// Create a constant expression containing a single `i32.const` instruction.
    pub fn i32_const(value: i32) -> Self {
        Self::new_insn(Instruction::I32Const(value))
    }

    /// Create a constant expression containing a single `i64.const` instruction.
    pub fn i64_const(value: i64) -> Self {
        Self::new_insn(Instruction::I64Const(value))
    }

    /// Create a constant expression containing a single `f32.const` instruction.
    pub fn f32_const(value: f32) -> Self {
        Self::new_insn(Instruction::F32Const(value))
    }

    /// Create a constant expression containing a single `f64.const` instruction.
    pub fn f64_const(value: f64) -> Self {
        Self::new_insn(Instruction::F64Const(value))
    }

    /// Create a constant expression containing a single `v128.const` instruction.
    pub fn v128_const(value: i128) -> Self {
        Self::new_insn(Instruction::V128Const(value))
    }

    /// Add a `global.get` instruction to this constant expression.
    pub fn with_global_get(self, index: u32) -> Self {
        self.with_insn(Instruction::GlobalGet(index))
    }

    /// Add a `ref.null` instruction to this constant expression.
    pub fn with_ref_null(self, ty: HeapType) -> Self {
        self.with_insn(Instruction::RefNull(ty))
    }

    /// Add a `ref.func` instruction to this constant expression.
    pub fn with_ref_func(self, func: u32) -> Self {
        self.with_insn(Instruction::RefFunc(func))
    }

    /// Add an `i32.const` instruction to this constant expression.
    pub fn with_i32_const(self, value: i32) -> Self {
        self.with_insn(Instruction::I32Const(value))
    }

    /// Add an `i64.const` instruction to this constant expression.
    pub fn with_i64_const(self, value: i64) -> Self {
        self.with_insn(Instruction::I64Const(value))
    }

    /// Add a `f32.const` instruction to this constant expression.
    pub fn with_f32_const(self, value: f32) -> Self {
        self.with_insn(Instruction::F32Const(value))
    }

    /// Add a `f64.const` instruction to this constant expression.
    pub fn with_f64_const(self, value: f64) -> Self {
        self.with_insn(Instruction::F64Const(value))
    }

    /// Add a `v128.const` instruction to this constant expression.
    pub fn with_v128_const(self, value: i128) -> Self {
        self.with_insn(Instruction::V128Const(value))
    }

    /// Add an `i32.add` instruction to this constant expression.
    pub fn with_i32_add(self) -> Self {
        self.with_insn(Instruction::I32Add)
    }

    /// Add an `i32.sub` instruction to this constant expression.
    pub fn with_i32_sub(self) -> Self {
        self.with_insn(Instruction::I32Sub)
    }

    /// Add an `i32.mul` instruction to this constant expression.
    pub fn with_i32_mul(self) -> Self {
        self.with_insn(Instruction::I32Mul)
    }

    /// Add an `i64.add` instruction to this constant expression.
    pub fn with_i64_add(self) -> Self {
        self.with_insn(Instruction::I64Add)
    }

    /// Add an `i64.sub` instruction to this constant expression.
    pub fn with_i64_sub(self) -> Self {
        self.with_insn(Instruction::I64Sub)
    }

    /// Add an `i64.mul` instruction to this constant expression.
    pub fn with_i64_mul(self) -> Self {
        self.with_insn(Instruction::I64Mul)
    }

    /// Returns the function, if any, referenced by this global.
    pub fn get_ref_func(&self) -> Option<u32> {
        let prefix = *self.bytes.get(0)?;
        // 0xd2 == `ref.func` opcode, and if that's found then load the leb
        // corresponding to the function index.
        if prefix != 0xd2 {
            return None;
        }
        leb128::read::unsigned(&mut &self.bytes[1..])
            .ok()?
            .try_into()
            .ok()
    }
}

impl Encode for ConstExpr {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.extend(&self.bytes);
        Instruction::End.encode(sink);
    }
}

/// An error when converting a `wasmparser::ConstExpr` into a
/// `wasm_encoder::ConstExpr`.
#[cfg(feature = "wasmparser")]
#[derive(Debug)]
pub enum ConstExprConversionError {
    /// There was an error when parsing the const expression.
    ParseError(wasmparser::BinaryReaderError),

    /// The const expression is invalid: not actually constant or something like
    /// that.
    Invalid,

    /// There was a type reference that was canonicalized and no longer
    /// references an index into a module's types space, so we cannot encode it
    /// into a Wasm binary again.
    CanonicalizedTypeReference,
}

#[cfg(feature = "wasmparser")]
impl std::fmt::Display for ConstExprConversionError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::ParseError(_e) => {
                write!(f, "There was an error when parsing the const expression")
            }
            Self::Invalid => write!(f, "The const expression was invalid"),
            Self::CanonicalizedTypeReference => write!(
                f,
                "There was a canonicalized type reference without type index information"
            ),
        }
    }
}

#[cfg(feature = "wasmparser")]
impl std::error::Error for ConstExprConversionError {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        match self {
            Self::ParseError(e) => Some(e),
            Self::Invalid | Self::CanonicalizedTypeReference => None,
        }
    }
}

#[cfg(feature = "wasmparser")]
impl<'a> TryFrom<wasmparser::ConstExpr<'a>> for ConstExpr {
    type Error = ConstExprConversionError;

    fn try_from(const_expr: wasmparser::ConstExpr) -> Result<Self, Self::Error> {
        let mut ops = const_expr.get_operators_reader().into_iter();

        let result = match ops.next() {
            Some(Ok(wasmparser::Operator::I32Const { value })) => ConstExpr::i32_const(value),
            Some(Ok(wasmparser::Operator::I64Const { value })) => ConstExpr::i64_const(value),
            Some(Ok(wasmparser::Operator::F32Const { value })) => {
                ConstExpr::f32_const(f32::from_bits(value.bits()))
            }
            Some(Ok(wasmparser::Operator::F64Const { value })) => {
                ConstExpr::f64_const(f64::from_bits(value.bits()))
            }
            Some(Ok(wasmparser::Operator::V128Const { value })) => {
                ConstExpr::v128_const(i128::from_le_bytes(*value.bytes()))
            }
            Some(Ok(wasmparser::Operator::RefNull { hty })) => ConstExpr::ref_null(
                HeapType::try_from(hty)
                    .map_err(|_| ConstExprConversionError::CanonicalizedTypeReference)?,
            ),
            Some(Ok(wasmparser::Operator::RefFunc { function_index })) => {
                ConstExpr::ref_func(function_index)
            }
            Some(Ok(wasmparser::Operator::GlobalGet { global_index })) => {
                ConstExpr::global_get(global_index)
            }

            // TODO: support the extended-const proposal.
            Some(Ok(_op)) => return Err(ConstExprConversionError::Invalid),

            Some(Err(e)) => return Err(ConstExprConversionError::ParseError(e)),
            None => return Err(ConstExprConversionError::Invalid),
        };

        match (ops.next(), ops.next()) {
            (Some(Ok(wasmparser::Operator::End)), None) => Ok(result),
            _ => Err(ConstExprConversionError::Invalid),
        }
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn function_new_with_locals_test() {
        use super::*;

        // Test the algorithm for conversion is correct
        let f1 = Function::new_with_locals_types([
            ValType::I32,
            ValType::I32,
            ValType::I64,
            ValType::F32,
            ValType::F32,
            ValType::F32,
            ValType::I32,
            ValType::I64,
            ValType::I64,
        ]);
        let f2 = Function::new([
            (2, ValType::I32),
            (1, ValType::I64),
            (3, ValType::F32),
            (1, ValType::I32),
            (2, ValType::I64),
        ]);

        assert_eq!(f1.bytes, f2.bytes)
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/custom.rs

Source (jump to first uncovered line)
use std::borrow::Cow;

use crate::{encoding_size, Encode, Section, SectionId};

/// A custom section holding arbitrary data.
#[derive(Clone, Debug)]
pub struct CustomSection<'a> {
    /// The name of this custom section.
    pub name: Cow<'a, str>,
    /// This custom section's data.
    pub data: Cow<'a, [u8]>,
}

impl Encode for CustomSection<'_> {
    fn encode(&self, sink: &mut Vec<u8>) {
        let encoded_name_len = encoding_size(u32::try_from(self.name.len()).unwrap());
        (encoded_name_len + self.name.len() + self.data.len()).encode(sink);
        self.name.encode(sink);
        sink.extend(&*self.data);
    }
}

impl Section for CustomSection<'_> {
    fn id(&self) -> u8 {
        SectionId::Custom.into()
    }
}

/// A raw custom section where the bytes specified contain the leb-encoded
/// length of the custom section, the custom section's name, and the custom
/// section's data.
#[derive(Clone, Debug)]
pub struct RawCustomSection<'a>(pub &'a [u8]);

impl Encode for RawCustomSection<'_> {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.extend(self.0);
    }
}

impl Section for RawCustomSection<'_> {
    fn id(&self) -> u8 {
        SectionId::Custom.into()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_custom_section() {
        let custom = CustomSection {
            name: "test".into(),
            data: Cow::Borrowed(&[11, 22, 33, 44]),
        };

        let mut encoded = vec![];
        custom.encode(&mut encoded);

        #[rustfmt::skip]
        assert_eq!(encoded, vec![
            // LEB128 length of section.
            9,
            // LEB128 length of name.
            4,
            // Name.
            b't', b'e', b's', b't',
            // Data.
            11, 22, 33, 44,
        ]);
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/data.rs

Source (jump to first uncovered line)
use crate::{encode_section, encoding_size, ConstExpr, Encode, Section, SectionId};

/// An encoder for the data section.
///
/// Data sections are only supported for modules.
///
/// # Example
///
/// ```
/// use wasm_encoder::{
///     ConstExpr, DataSection, Instruction, MemorySection, MemoryType,
///     Module,
/// };
///
/// let mut memory = MemorySection::new();
/// memory.memory(MemoryType {
///     minimum: 1,
///     maximum: None,
///     memory64: false,
///     shared: false,
///     page_size_log2: None,
/// });
///
/// let mut data = DataSection::new();
/// let memory_index = 0;
/// let offset = ConstExpr::i32_const(42);
/// let segment_data = b"hello";
/// data.active(memory_index, &offset, segment_data.iter().copied());
///
/// let mut module = Module::new();
/// module
///     .section(&memory)
///     .section(&data);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Default, Debug)]
pub struct DataSection {
    bytes: Vec<u8>,
    num_added: u32,
}

/// A segment in the data section.
#[derive(Clone, Debug)]
pub struct DataSegment<'a, D> {
    /// This data segment's mode.
    pub mode: DataSegmentMode<'a>,
    /// This data segment's data.
    pub data: D,
}

/// A data segment's mode.
#[derive(Clone, Debug)]
pub enum DataSegmentMode<'a> {
    /// An active data segment.
    Active {
        /// The memory this segment applies to.
        memory_index: u32,
        /// The offset where this segment's data is initialized at.
        offset: &'a ConstExpr,
    },
    /// A passive data segment.
    ///
    /// Passive data segments are part of the bulk memory proposal.
    Passive,
}

impl DataSection {
    /// Create a new data section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of data segments in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define a data segment.
    pub fn segment<D>(&mut self, segment: DataSegment<D>) -> &mut Self
    where
        D: IntoIterator<Item = u8>,
        D::IntoIter: ExactSizeIterator,
    {
        match segment.mode {
            DataSegmentMode::Passive => {
                self.bytes.push(0x01);
            }
            DataSegmentMode::Active {
                memory_index: 0,
                offset,
            } => {
                self.bytes.push(0x00);
                offset.encode(&mut self.bytes);
            }
            DataSegmentMode::Active {
                memory_index,
                offset,
            } => {
                self.bytes.push(0x02);
                memory_index.encode(&mut self.bytes);
                offset.encode(&mut self.bytes);
            }
        }

        let data = segment.data.into_iter();
        data.len().encode(&mut self.bytes);
        self.bytes.extend(data);

        self.num_added += 1;
        self
    }

    /// Define an active data segment.
    pub fn active<D>(&mut self, memory_index: u32, offset: &ConstExpr, data: D) -> &mut Self
    where
        D: IntoIterator<Item = u8>,
        D::IntoIter: ExactSizeIterator,
    {
        self.segment(DataSegment {
            mode: DataSegmentMode::Active {
                memory_index,
                offset,
            },
            data,
        })
    }

    /// Define a passive data segment.
    ///
    /// Passive data segments are part of the bulk memory proposal.
    pub fn passive<D>(&mut self, data: D) -> &mut Self
    where
        D: IntoIterator<Item = u8>,
        D::IntoIter: ExactSizeIterator,
    {
        self.segment(DataSegment {
            mode: DataSegmentMode::Passive,
            data,
        })
    }

    /// Copy an already-encoded data segment into this data section.
    pub fn raw(&mut self, already_encoded_data_segment: &[u8]) -> &mut Self {
        self.bytes.extend_from_slice(already_encoded_data_segment);
        self.num_added += 1;
        self
    }
}

impl Encode for DataSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for DataSection {
    fn id(&self) -> u8 {
        SectionId::Data.into()
    }
}

/// An encoder for the data count section.
#[derive(Clone, Copy, Debug)]
pub struct DataCountSection {
    /// The number of segments in the data section.
    pub count: u32,
}

impl Encode for DataCountSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encoding_size(self.count).encode(sink);
        self.count.encode(sink);
    }
}

impl Section for DataCountSection {
    fn id(&self) -> u8 {
        SectionId::DataCount.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/dump.rs

Source (jump to first uncovered line)
use std::borrow::Cow;

use crate::{CustomSection, Encode, Section};

/// The "core" custom section for coredumps, as described in the
/// [tool-conventions
/// repository](https://github.com/WebAssembly/tool-conventions/blob/main/Coredump.md).
///
/// There are four sections that comprise a core dump:
///     - "core", which contains the name of the core dump
///     - "coremodules", a listing of modules
///     - "coreinstances", a listing of module instances
///     - "corestack", a listing of frames for a specific thread
///
/// # Example of how these could be constructed and encoded into a module:
///
/// ```
/// use wasm_encoder::{
///     CoreDumpInstancesSection, CoreDumpModulesSection, CoreDumpSection, CoreDumpStackSection,
///     CoreDumpValue, Module,
/// };
/// let core = CoreDumpSection::new("MyModule.wasm");
///
/// let mut modules = CoreDumpModulesSection::new();
/// modules.module("my_module");
///
/// let mut instances = CoreDumpInstancesSection::new();
/// let module_idx = 0;
/// let memories = vec![1];
/// let globals = vec![2];
/// instances.instance(module_idx, memories, globals);
///
/// let mut thread = CoreDumpStackSection::new("main");
/// let instance_index = 0;
/// let func_index = 42;
/// let code_offset = 0x1234;
/// let locals = vec![CoreDumpValue::I32(1)];
/// let stack = vec![CoreDumpValue::I32(2)];
/// thread.frame(instance_index, func_index, code_offset, locals, stack);
///
/// let mut module = Module::new();
/// module.section(&core);
/// module.section(&modules);
/// module.section(&instances);
/// module.section(&thread);
/// ```
#[derive(Clone, Debug, Default)]
pub struct CoreDumpSection {
    name: String,
}

impl CoreDumpSection {
    /// Create a new core dump section encoder
    pub fn new(name: impl Into<String>) -> Self {
        let name = name.into();
        CoreDumpSection { name }
    }

    /// View the encoded section as a CustomSection.
    fn as_custom<'a>(&'a self) -> CustomSection<'a> {
        let mut data = vec![0];
        self.name.encode(&mut data);
        CustomSection {
            name: "core".into(),
            data: Cow::Owned(data),
        }
    }
}

impl Encode for CoreDumpSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.as_custom().encode(sink);
    }
}

impl Section for CoreDumpSection {
    fn id(&self) -> u8 {
        crate::core::SectionId::Custom as u8
    }
}

/// The "coremodules" custom section for coredumps which lists the names of the
/// modules
///
/// # Example
///
/// ```
/// use wasm_encoder::{CoreDumpModulesSection, Module};
/// let mut modules_section = CoreDumpModulesSection::new();
/// modules_section.module("my_module");
/// let mut module = Module::new();
/// module.section(&modules_section);
/// ```
#[derive(Debug)]
pub struct CoreDumpModulesSection {
    num_added: u32,
    bytes: Vec<u8>,
}

impl CoreDumpModulesSection {
    /// Create a new core dump modules section encoder.
    pub fn new() -> Self {
        CoreDumpModulesSection {
            bytes: vec![],
            num_added: 0,
        }
    }

    /// View the encoded section as a CustomSection.
    pub fn as_custom(&self) -> CustomSection<'_> {
        let mut data = vec![];
        self.num_added.encode(&mut data);
        data.extend(self.bytes.iter().copied());
        CustomSection {
            name: "coremodules".into(),
            data: Cow::Owned(data),
        }
    }

    /// Encode a module name into the section's bytes.
    pub fn module(&mut self, module_name: impl AsRef<str>) -> &mut Self {
        self.bytes.push(0x0);
        module_name.as_ref().encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// The number of modules that are encoded in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }
}

impl Encode for CoreDumpModulesSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.as_custom().encode(sink);
    }
}

impl Section for CoreDumpModulesSection {
    fn id(&self) -> u8 {
        crate::core::SectionId::Custom as u8
    }
}

/// The "coreinstances" section for the core dump
#[derive(Debug)]
pub struct CoreDumpInstancesSection {
    num_added: u32,
    bytes: Vec<u8>,
}

impl CoreDumpInstancesSection {
    /// Create a new core dump instances section encoder.
    pub fn new() -> Self {
        CoreDumpInstancesSection {
            bytes: vec![],
            num_added: 0,
        }
    }

    /// View the encoded section as a CustomSection.
    pub fn as_custom(&self) -> CustomSection<'_> {
        let mut data = vec![];
        self.num_added.encode(&mut data);
        data.extend(self.bytes.iter().copied());
        CustomSection {
            name: "coreinstances".into(),
            data: Cow::Owned(data),
        }
    }

    /// Encode an instance into the section's bytes.
    pub fn instance<M, G>(&mut self, module_index: u32, memories: M, globals: G) -> &mut Self
    where
        M: IntoIterator<Item = u32>,
        <M as IntoIterator>::IntoIter: ExactSizeIterator,
        G: IntoIterator<Item = u32>,
        <G as IntoIterator>::IntoIter: ExactSizeIterator,
    {
        self.bytes.push(0x0);
        module_index.encode(&mut self.bytes);
        crate::encode_vec(memories, &mut self.bytes);
        crate::encode_vec(globals, &mut self.bytes);
        self.num_added += 1;
        self
    }

    /// The number of modules that are encoded in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }
}

impl Encode for CoreDumpInstancesSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.as_custom().encode(sink);
    }
}

impl Section for CoreDumpInstancesSection {
    fn id(&self) -> u8 {
        crate::core::SectionId::Custom as u8
    }
}

/// A "corestack" custom section as described in the [tool-conventions
/// repository](https://github.com/WebAssembly/tool-conventions/blob/main/Coredump.md)
///
/// # Example
///
/// ```
/// use wasm_encoder::{CoreDumpStackSection, Module, CoreDumpValue};
/// let mut thread = CoreDumpStackSection::new("main");
///
/// let instance_index = 0;
/// let func_index = 42;
/// let code_offset = 0x1234;
/// let locals = vec![CoreDumpValue::I32(1)];
/// let stack = vec![CoreDumpValue::I32(2)];
/// thread.frame(instance_index, func_index, code_offset, locals, stack);
///
/// let mut module = Module::new();
/// module.section(&thread);
/// ```
#[derive(Clone, Debug, Default)]
pub struct CoreDumpStackSection {
    frame_bytes: Vec<u8>,
    count: u32,
    name: String,
}

impl CoreDumpStackSection {
    /// Create a new core dump stack section encoder.
    pub fn new(name: impl Into<String>) -> Self {
        let name = name.into();
        CoreDumpStackSection {
            frame_bytes: Vec::new(),
            count: 0,
            name,
        }
    }

    /// Add a stack frame to this coredump stack section.
    pub fn frame<L, S>(
        &mut self,
        instanceidx: u32,
        funcidx: u32,
        codeoffset: u32,
        locals: L,
        stack: S,
    ) -> &mut Self
    where
        L: IntoIterator<Item = CoreDumpValue>,
        <L as IntoIterator>::IntoIter: ExactSizeIterator,
        S: IntoIterator<Item = CoreDumpValue>,
        <S as IntoIterator>::IntoIter: ExactSizeIterator,
    {
        self.count += 1;
        self.frame_bytes.push(0);
        instanceidx.encode(&mut self.frame_bytes);
        funcidx.encode(&mut self.frame_bytes);
        codeoffset.encode(&mut self.frame_bytes);
        crate::encode_vec(locals, &mut self.frame_bytes);
        crate::encode_vec(stack, &mut self.frame_bytes);
        self
    }

    /// View the encoded section as a CustomSection.
    pub fn as_custom<'a>(&'a self) -> CustomSection<'a> {
        let mut data = vec![0];
        self.name.encode(&mut data);
        self.count.encode(&mut data);
        data.extend(&self.frame_bytes);
        CustomSection {
            name: "corestack".into(),
            data: Cow::Owned(data),
        }
    }
}

impl Encode for CoreDumpStackSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.as_custom().encode(sink);
    }
}

impl Section for CoreDumpStackSection {
    fn id(&self) -> u8 {
        crate::core::SectionId::Custom as u8
    }
}

/// Local and stack values are encoded using one byte for the type (similar to
/// Wasm's Number Types) followed by bytes representing the actual value
/// See the tool-conventions repo for more details.
#[derive(Clone, Debug)]
pub enum CoreDumpValue {
    /// a missing value (usually missing because it was optimized out)
    Missing,
    /// An i32 value
    I32(i32),
    /// An i64 value
    I64(i64),
    /// An f32 value
    F32(f32),
    /// An f64 value
    F64(f64),
}

impl Encode for CoreDumpValue {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            CoreDumpValue::Missing => sink.push(0x01),
            CoreDumpValue::I32(x) => {
                sink.push(0x7F);
                x.encode(sink);
            }
            CoreDumpValue::I64(x) => {
                sink.push(0x7E);
                x.encode(sink);
            }
            CoreDumpValue::F32(x) => {
                sink.push(0x7D);
                x.encode(sink);
            }
            CoreDumpValue::F64(x) => {
                sink.push(0x7C);
                x.encode(sink);
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::Module;
    use wasmparser::{KnownCustom, Parser, Payload};

    // Create new core dump section and test whether it is properly encoded and
    // parsed back out by wasmparser
    #[test]
    fn test_roundtrip_core() {
        let core = CoreDumpSection::new("test.wasm");
        let mut module = Module::new();
        module.section(&core);

        let wasm_bytes = module.finish();

        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
        match parser.next() {
            Some(Ok(Payload::Version { .. })) => {}
            _ => panic!(""),
        }

        let payload = parser
            .next()
            .expect("parser is not empty")
            .expect("element is a payload");
        match payload {
            Payload::CustomSection(section) => {
                assert_eq!(section.name(), "core");
                let core = match section.as_known() {
                    KnownCustom::CoreDump(s) => s,
                    _ => panic!("not coredump"),
                };
                assert_eq!(core.name, "test.wasm");
            }
            _ => panic!("unexpected payload"),
        }
    }

    #[test]
    fn test_roundtrip_coremodules() {
        let mut coremodules = CoreDumpModulesSection::new();
        coremodules.module("test_module");

        let mut module = crate::Module::new();
        module.section(&coremodules);

        let wasm_bytes = module.finish();

        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
        match parser.next() {
            Some(Ok(Payload::Version { .. })) => {}
            _ => panic!(""),
        }

        let payload = parser
            .next()
            .expect("parser is not empty")
            .expect("element is a payload");
        match payload {
            Payload::CustomSection(section) => {
                assert_eq!(section.name(), "coremodules");
                let modules = match section.as_known() {
                    KnownCustom::CoreDumpModules(s) => s,
                    _ => panic!("not coremodules"),
                };
                assert_eq!(modules.modules[0], "test_module");
            }
            _ => panic!("unexpected payload"),
        }
    }

    #[test]
    fn test_roundtrip_coreinstances() {
        let mut coreinstances = CoreDumpInstancesSection::new();
        let module_index = 0;
        let memories = vec![42];
        let globals = vec![17];
        coreinstances.instance(module_index, memories, globals);

        let mut module = Module::new();
        module.section(&coreinstances);
        let wasm_bytes = module.finish();

        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
        match parser.next() {
            Some(Ok(Payload::Version { .. })) => {}
            _ => panic!(""),
        }

        let payload = parser
            .next()
            .expect("parser is not empty")
            .expect("element is a payload");
        match payload {
            Payload::CustomSection(section) => {
                assert_eq!(section.name(), "coreinstances");
                let coreinstances = match section.as_known() {
                    KnownCustom::CoreDumpInstances(s) => s,
                    _ => panic!("not coreinstances"),
                };
                assert_eq!(coreinstances.instances.len(), 1);
                let instance = coreinstances
                    .instances
                    .first()
                    .expect("instance is encoded");
                assert_eq!(instance.module_index, 0);
                assert_eq!(instance.memories.len(), 1);
                assert_eq!(instance.globals.len(), 1);
            }
            _ => panic!("unexpected payload"),
        }
    }

    // Create new corestack section and test whether it is properly encoded and
    // parsed back out by wasmparser
    #[test]
    fn test_roundtrip_corestack() {
        let mut corestack = CoreDumpStackSection::new("main");
        corestack.frame(
            0,
            12,
            0,
            vec![CoreDumpValue::I32(10)],
            vec![CoreDumpValue::I32(42)],
        );
        let mut module = Module::new();
        module.section(&corestack);
        let wasm_bytes = module.finish();

        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
        match parser.next() {
            Some(Ok(Payload::Version { .. })) => {}
            _ => panic!(""),
        }

        let payload = parser
            .next()
            .expect("parser is not empty")
            .expect("element is a payload");
        match payload {
            Payload::CustomSection(section) => {
                assert_eq!(section.name(), "corestack");
                let corestack = match section.as_known() {
                    KnownCustom::CoreDumpStack(s) => s,
                    _ => panic!("not a corestack section"),
                };
                assert_eq!(corestack.name, "main");
                assert_eq!(corestack.frames.len(), 1);
                let frame = corestack
                    .frames
                    .first()
                    .expect("frame is encoded in corestack");
                assert_eq!(frame.instanceidx, 0);
                assert_eq!(frame.funcidx, 12);
                assert_eq!(frame.codeoffset, 0);
                assert_eq!(frame.locals.len(), 1);
                match frame.locals.first().expect("frame contains a local") {
                    &wasmparser::CoreDumpValue::I32(val) => assert_eq!(val, 10),
                    _ => panic!("unexpected local value"),
                }
                assert_eq!(frame.stack.len(), 1);
                match frame.stack.first().expect("stack contains a value") {
                    &wasmparser::CoreDumpValue::I32(val) => assert_eq!(val, 42),
                    _ => panic!("unexpected stack value"),
                }
            }
            _ => panic!("unexpected payload"),
        }
    }

    #[test]
    fn test_encode_coredump_section() {
        let core = CoreDumpSection::new("test");

        let mut encoded = vec![];
        core.encode(&mut encoded);

        #[rustfmt::skip]
        assert_eq!(encoded, vec![
            // section length
            11,
            // name length
            4,
            // section name (core)
            b'c',b'o',b'r',b'e',
            // process-info (0, data length, data)
            0, 4, b't', b'e', b's', b't',
        ]);
    }

    #[test]
    fn test_encode_coremodules_section() {
        let mut modules = CoreDumpModulesSection::new();
        modules.module("mod1");
        modules.module("mod2");

        let mut encoded = vec![];
        modules.encode(&mut encoded);

        #[rustfmt::skip]
        assert_eq!(encoded, vec![
            // section length
            25,
            // name length
            11,
            // section name (coremodules)
            b'c',b'o',b'r',b'e',b'm',b'o',b'd',b'u',b'l',b'e',b's',
            // module count
            2,
            // 0x0, name-length, module name (mod1)
            0x0, 4, b'm',b'o',b'd',b'1',
            // 0x0, name-length, module name (mod2)
            0x0, 4, b'm',b'o',b'd',b'2'
        ]);
    }

    #[test]
    fn test_encode_coreinstances_section() {
        let mut instances = CoreDumpInstancesSection::new();
        instances.instance(0, vec![42], vec![17]);

        let mut encoded = vec![];
        instances.encode(&mut encoded);

        #[rustfmt::skip]
        assert_eq!(encoded, vec![
            // section length
            21,
            // name length
            13,
            // section name (coreinstances)
            b'c',b'o',b'r',b'e',b'i',b'n',b's',b't',b'a',b'n',b'c',b'e',b's',
            // instance count
            1,
            // 0x0, module_idx
            0x0, 0,
            // memories count, memories
            1, 42,
            // globals count, globals
            1, 17
        ]);
    }

    #[test]
    fn test_encode_corestack_section() {
        let mut thread = CoreDumpStackSection::new("main");
        thread.frame(
            0,
            42,
            51,
            vec![CoreDumpValue::I32(1)],
            vec![CoreDumpValue::I32(2)],
        );

        let mut encoded = vec![];
        thread.encode(&mut encoded);

        #[rustfmt::skip]
        assert_eq!(
            encoded,
            vec![
                // section length
                27,
                // length of name.
                9,
                // section name (corestack)
                b'c',b'o',b'r',b'e',b's',b't',b'a',b'c',b'k',
                // 0x0, thread name length
                0, 4,
                // thread name (main)
                b'm',b'a',b'i',b'n',
                // frame count
                1,
                // 0x0, instanceidx, funcidx, codeoffset
                0, 0, 42, 51,
                // local count
                1,
                // local value type
                0x7F,
                // local value
                1,
                // stack count
                1,
                // stack value type
                0x7F,
                // stack value
                2

            ]
        );
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/elements.rs

Source (jump to first uncovered line)
use crate::{encode_section, ConstExpr, Encode, RefType, Section, SectionId};

/// An encoder for the element section.
///
/// Element sections are only supported for modules.
///
/// # Example
///
/// ```
/// use wasm_encoder::{
///     Elements, ElementSection, Module, TableSection, TableType,
///     RefType, ConstExpr
/// };
///
/// let mut tables = TableSection::new();
/// tables.table(TableType {
///     element_type: RefType::FUNCREF,
///     minimum: 128,
///     maximum: None,
///     table64: false,
/// });
///
/// let mut elements = ElementSection::new();
/// let table_index = 0;
/// let offset = ConstExpr::i32_const(42);
/// let functions = Elements::Functions(&[
///     // Function indices...
/// ]);
/// elements.active(Some(table_index), &offset, functions);
///
/// let mut module = Module::new();
/// module
///     .section(&tables)
///     .section(&elements);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Default, Debug)]
pub struct ElementSection {
    bytes: Vec<u8>,
    num_added: u32,
}

/// A sequence of elements in a segment in the element section.
#[derive(Clone, Copy, Debug)]
pub enum Elements<'a> {
    /// A sequences of references to functions by their indices.
    Functions(&'a [u32]),
    /// A sequence of reference expressions.
    Expressions(RefType, &'a [ConstExpr]),
}

/// An element segment's mode.
#[derive(Clone, Debug)]
pub enum ElementMode<'a> {
    /// A passive element segment.
    ///
    /// Passive segments are part of the bulk memory proposal.
    Passive,
    /// A declared element segment.
    ///
    /// Declared segments are part of the bulk memory proposal.
    Declared,
    /// An active element segment.
    Active {
        /// The table index.
        ///
        /// `Active` element specifying a `None` table forces the MVP encoding and refers to the
        /// 0th table holding `funcref`s. Non-`None` tables use the encoding introduced with the
        /// bulk memory proposal and can refer to tables with any valid reference type.
        table: Option<u32>,
        /// The offset within the table to place this segment.
        offset: &'a ConstExpr,
    },
}

/// An element segment in the element section.
#[derive(Clone, Debug)]
pub struct ElementSegment<'a> {
    /// The element segment's mode.
    pub mode: ElementMode<'a>,
    /// This segment's elements.
    pub elements: Elements<'a>,
}

impl ElementSection {
    /// Create a new element section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of element segments in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define an element segment.
    pub fn segment<'a>(&mut self, segment: ElementSegment<'a>) -> &mut Self {
        let expr_bit = match segment.elements {
            Elements::Expressions(..) => 0b100u32,
            Elements::Functions(_) => 0b000u32,
        };
        let mut encode_type = false;
        match &segment.mode {
            ElementMode::Passive => {
                (0x01 | expr_bit).encode(&mut self.bytes);
                encode_type = true;
            }
            ElementMode::Active { table, offset } => {
                match (table, &segment.elements) {
                    // If the `table` is not specified then the 0x00 encoding
                    // can be used with either function indices or expressions
                    // that have a `funcref` type.
                    (None, Elements::Functions(_) | Elements::Expressions(RefType::FUNCREF, _)) => {
                        (/* 0x00 | */expr_bit).encode(&mut self.bytes);
                    }

                    // ... otherwise fall through for all other expressions here
                    // with table 0 or an explicitly specified table to the 0x02
                    // encoding.
                    (None, Elements::Expressions(..)) | (Some(_), _) => {
                        (0x02 | expr_bit).encode(&mut self.bytes);
                        table.unwrap_or(0).encode(&mut self.bytes);
                        encode_type = true;
                    }
                }
                offset.encode(&mut self.bytes);
            }
            ElementMode::Declared => {
                (0x03 | expr_bit).encode(&mut self.bytes);
                encode_type = true;
            }
        }

        match segment.elements {
            Elements::Functions(fs) => {
                if encode_type {
                    // elemkind == funcref
                    self.bytes.push(0x00);
                }
                fs.encode(&mut self.bytes);
            }
            Elements::Expressions(ty, e) => {
                if encode_type {
                    ty.encode(&mut self.bytes);
                }
                e.len().encode(&mut self.bytes);
                for expr in e {
                    expr.encode(&mut self.bytes);
                }
            }
        }

        self.num_added += 1;
        self
    }

    /// Define an active element segment.
    ///
    /// `Active` element specifying a `None` table forces the MVP encoding and refers to the 0th
    /// table holding `funcref`s. Non-`None` tables use the encoding introduced with the bulk
    /// memory proposal and can refer to tables with any valid reference type.
    pub fn active(
        &mut self,
        table_index: Option<u32>,
        offset: &ConstExpr,
        elements: Elements<'_>,
    ) -> &mut Self {
        self.segment(ElementSegment {
            mode: ElementMode::Active {
                table: table_index,
                offset,
            },
            elements,
        })
    }

    /// Encode a passive element segment.
    ///
    /// Passive segments are part of the bulk memory proposal.
    pub fn passive<'a>(&mut self, elements: Elements<'a>) -> &mut Self {
        self.segment(ElementSegment {
            mode: ElementMode::Passive,
            elements,
        })
    }

    /// Encode a declared element segment.
    ///
    /// Declared segments are part of the bulk memory proposal.
    pub fn declared<'a>(&mut self, elements: Elements<'a>) -> &mut Self {
        self.segment(ElementSegment {
            mode: ElementMode::Declared,
            elements,
        })
    }

    /// Copy a raw, already-encoded element segment into this elements section.
    pub fn raw(&mut self, raw_bytes: &[u8]) -> &mut Self {
        self.bytes.extend_from_slice(raw_bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for ElementSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for ElementSection {
    fn id(&self) -> u8 {
        SectionId::Element.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/exports.rs

Source (jump to first uncovered line)
use super::{
    CORE_FUNCTION_SORT, CORE_GLOBAL_SORT, CORE_MEMORY_SORT, CORE_TABLE_SORT, CORE_TAG_SORT,
};
use crate::{encode_section, Encode, Section, SectionId};

/// Represents the kind of an export from a WebAssembly module.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
#[repr(u8)]
pub enum ExportKind {
    /// The export is a function.
    Func = CORE_FUNCTION_SORT,
    /// The export is a table.
    Table = CORE_TABLE_SORT,
    /// The export is a memory.
    Memory = CORE_MEMORY_SORT,
    /// The export is a global.
    Global = CORE_GLOBAL_SORT,
    /// The export is a tag.
    Tag = CORE_TAG_SORT,
}

impl Encode for ExportKind {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.push(*self as u8);
    }
}

#[cfg(feature = "wasmparser")]
impl From<wasmparser::ExternalKind> for ExportKind {
    fn from(external_kind: wasmparser::ExternalKind) -> Self {
        match external_kind {
            wasmparser::ExternalKind::Func => ExportKind::Func,
            wasmparser::ExternalKind::Table => ExportKind::Table,
            wasmparser::ExternalKind::Memory => ExportKind::Memory,
            wasmparser::ExternalKind::Global => ExportKind::Global,
            wasmparser::ExternalKind::Tag => ExportKind::Tag,
        }
    }
}

/// An encoder for the export section of WebAssembly module.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Module, ExportSection, ExportKind};
///
/// let mut exports = ExportSection::new();
/// exports.export("foo", ExportKind::Func, 0);
///
/// let mut module = Module::new();
/// module.section(&exports);
///
/// let bytes = module.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct ExportSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl ExportSection {
    /// Create a new export section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of exports in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define an export in the export section.
    pub fn export(&mut self, name: &str, kind: ExportKind, index: u32) -> &mut Self {
        name.encode(&mut self.bytes);
        kind.encode(&mut self.bytes);
        index.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for ExportSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for ExportSection {
    fn id(&self) -> u8 {
        SectionId::Export.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/functions.rs

Source (jump to first uncovered line)
use crate::{encode_section, Encode, Section, SectionId};

/// An encoder for the function section of WebAssembly modules.
///
/// # Example
///
/// ```
/// use wasm_encoder::{Module, FunctionSection, ValType};
///
/// let mut functions = FunctionSection::new();
/// let type_index = 0;
/// functions.function(type_index);
///
/// let mut module = Module::new();
/// module.section(&functions);
///
/// // Note: this will generate an invalid module because we didn't generate a
/// // code section containing the function body. See the documentation for
/// // `CodeSection` for details.
///
/// let bytes = module.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct FunctionSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl FunctionSection {
    /// Construct a new module function section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of functions in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define a function in a module's function section.
    pub fn function(&mut self, type_index: u32) -> &mut Self {
        type_index.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for FunctionSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for FunctionSection {
    fn id(&self) -> u8 {
        SectionId::Function.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/globals.rs

Source (jump to first uncovered line)
use crate::{encode_section, ConstExpr, Encode, Section, SectionId, ValType};

/// An encoder for the global section.
///
/// Global sections are only supported for modules.
///
/// # Example
///
/// ```
/// use wasm_encoder::{ConstExpr, Module, GlobalSection, GlobalType, Instruction, ValType};
///
/// let mut globals = GlobalSection::new();
/// globals.global(
///     GlobalType {
///         val_type: ValType::I32,
///         mutable: false,
///         shared: false,
///     },
///     &ConstExpr::i32_const(42),
/// );
///
/// let mut module = Module::new();
/// module.section(&globals);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Default, Debug)]
pub struct GlobalSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl GlobalSection {
    /// Create a new global section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of globals in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define a global.
    pub fn global(&mut self, global_type: GlobalType, init_expr: &ConstExpr) -> &mut Self {
        global_type.encode(&mut self.bytes);
        init_expr.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// Add a raw byte slice into this code section as a global.
    pub fn raw(&mut self, data: &[u8]) -> &mut Self {
        self.bytes.extend(data);
        self.num_added += 1;
        self
    }
}

impl Encode for GlobalSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for GlobalSection {
    fn id(&self) -> u8 {
        SectionId::Global.into()
    }
}

/// A global's type.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
pub struct GlobalType {
    /// This global's value type.
    pub val_type: ValType,
    /// Whether this global is mutable or not.
    pub mutable: bool,
    /// Whether this global is shared or not.
    pub shared: bool,
}

impl Encode for GlobalType {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.val_type.encode(sink);
        let mut flag = 0;
        if self.mutable {
            flag |= 0b01;
        }
        if self.shared {
            flag |= 0b10;
        }
        sink.push(flag);
    }
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::GlobalType> for GlobalType {
    type Error = ();
    fn try_from(global_ty: wasmparser::GlobalType) -> Result<Self, Self::Error> {
        Ok(GlobalType {
            val_type: global_ty.content_type.try_into()?,
            mutable: global_ty.mutable,
            shared: global_ty.shared,
        })
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/imports.rs

Source (jump to first uncovered line)
use crate::{
    encode_section, Encode, GlobalType, MemoryType, Section, SectionId, TableType, TagType,
    CORE_FUNCTION_SORT, CORE_GLOBAL_SORT, CORE_MEMORY_SORT, CORE_TABLE_SORT, CORE_TAG_SORT,
};

/// The type of an entity.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum EntityType {
    /// A function type.
    ///
    /// The value is an index into the types section.
    Function(u32),
    /// A table type.
    Table(TableType),
    /// A memory type.
    Memory(MemoryType),
    /// A global type.
    Global(GlobalType),
    /// A tag type.
    ///
    /// This variant is used with the exception handling proposal.
    Tag(TagType),
}

impl Encode for EntityType {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            Self::Function(i) => {
                sink.push(CORE_FUNCTION_SORT);
                i.encode(sink);
            }
            Self::Table(t) => {
                sink.push(CORE_TABLE_SORT);
                t.encode(sink);
            }
            Self::Memory(t) => {
                sink.push(CORE_MEMORY_SORT);
                t.encode(sink);
            }
            Self::Global(t) => {
                sink.push(CORE_GLOBAL_SORT);
                t.encode(sink);
            }
            Self::Tag(t) => {
                sink.push(CORE_TAG_SORT);
                t.encode(sink);
            }
        }
    }
}

impl From<TableType> for EntityType {
    fn from(t: TableType) -> Self {
        Self::Table(t)
    }
}

impl From<MemoryType> for EntityType {
    fn from(t: MemoryType) -> Self {
        Self::Memory(t)
    }
}

impl From<GlobalType> for EntityType {
    fn from(t: GlobalType) -> Self {
        Self::Global(t)
    }
}

impl From<TagType> for EntityType {
    fn from(t: TagType) -> Self {
        Self::Tag(t)
    }
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::TypeRef> for EntityType {
    type Error = ();
    fn try_from(type_ref: wasmparser::TypeRef) -> Result<Self, Self::Error> {
        Ok(match type_ref {
            wasmparser::TypeRef::Func(i) => EntityType::Function(i),
            wasmparser::TypeRef::Table(t) => EntityType::Table(t.try_into()?),
            wasmparser::TypeRef::Memory(m) => EntityType::Memory(m.into()),
            wasmparser::TypeRef::Global(g) => EntityType::Global(g.try_into()?),
            wasmparser::TypeRef::Tag(t) => EntityType::Tag(t.into()),
        })
    }
}

/// An encoder for the import section of WebAssembly modules.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{MemoryType, Module, ImportSection};
///
/// let mut imports = ImportSection::new();
/// imports.import(
///     "env",
///     "memory",
///     MemoryType {
///         minimum: 1,
///         maximum: None,
///         memory64: false,
///         shared: false,
///         page_size_log2: None,
///     }
/// );
///
/// let mut module = Module::new();
/// module.section(&imports);
///
/// let bytes = module.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct ImportSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl ImportSection {
    /// Create a new import section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of imports in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define an import in the import section.
    pub fn import(&mut self, module: &str, field: &str, ty: impl Into<EntityType>) -> &mut Self {
        module.encode(&mut self.bytes);
        field.encode(&mut self.bytes);
        ty.into().encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for ImportSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for ImportSection {
    fn id(&self) -> u8 {
        SectionId::Import.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/linking.rs

Source (jump to first uncovered line)
use std::borrow::Cow;

use crate::{encode_section, CustomSection, Encode, Section, SectionId};

const VERSION: u32 = 2;

/// An encoder for the [linking custom
/// section](https://github.com/WebAssembly/tool-conventions/blob/master/Linking.md#linking-metadata-section).
///
/// This section is a non-standard convention that is supported by the LLVM
/// toolchain. It, along with associated "reloc.*" custom sections, allows you
/// to treat a Wasm module as a low-level object file that can be linked with
/// other Wasm object files to produce a final, complete Wasm module.
///
/// The linking section must come before the reloc sections.
///
/// # Example
///
/// ```
/// use wasm_encoder::{LinkingSection, Module, SymbolTable};
///
/// // Create a new linking section.
/// let mut linking = LinkingSection::new();
///
/// // Define a symbol table.
/// let mut sym_tab = SymbolTable::new();
///
/// // Define a function symbol in the symbol table.
/// let flags = SymbolTable::WASM_SYM_BINDING_LOCAL | SymbolTable::WASM_SYM_EXPORTED;
/// let func_index = 42;
/// let sym_name = "my_exported_func";
/// sym_tab.function(flags, func_index, Some(sym_name));
///
/// // Add the symbol table to our linking section.
/// linking.symbol_table(&sym_tab);
///
/// // Add the linking section to a new Wasm module and get the encoded bytes.
/// let mut module = Module::new();
/// module.section(&linking);
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Debug)]
pub struct LinkingSection {
    bytes: Vec<u8>,
}

impl LinkingSection {
    /// Construct a new encoder for the linking custom section.
    pub fn new() -> Self {
        Self::default()
    }

    // TODO: `fn segment_info` for the `WASM_SEGMENT_INFO` linking subsection.

    // TODO: `fn init_funcs` for the `WASM_INIT_FUNCS` linking subsection.

    // TODO: `fn comdat_info` for the `WASM_COMDAT_INFO` linking subsection.

    /// Add a symbol table subsection.
    pub fn symbol_table(&mut self, symbol_table: &SymbolTable) -> &mut Self {
        symbol_table.encode(&mut self.bytes);
        self
    }
}

impl Default for LinkingSection {
    fn default() -> Self {
        let mut bytes = Vec::new();
        VERSION.encode(&mut bytes);
        Self { bytes }
    }
}

impl Encode for LinkingSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        CustomSection {
            name: "linking".into(),
            data: Cow::Borrowed(&self.bytes),
        }
        .encode(sink);
    }
}

impl Section for LinkingSection {
    fn id(&self) -> u8 {
        SectionId::Custom.into()
    }
}

#[allow(unused)]
const WASM_SEGMENT_INFO: u8 = 5;
#[allow(unused)]
const WASM_INIT_FUNCS: u8 = 6;
#[allow(unused)]
const WASM_COMDAT_INFO: u8 = 7;
const WASM_SYMBOL_TABLE: u8 = 8;

/// A subsection of the [linking custom section][crate::LinkingSection] that
/// provides extra information about the symbols present in this Wasm object
/// file.
#[derive(Clone, Debug, Default)]
pub struct SymbolTable {
    bytes: Vec<u8>,
    num_added: u32,
}

const SYMTAB_FUNCTION: u32 = 0;
const SYMTAB_DATA: u32 = 1;
const SYMTAB_GLOBAL: u32 = 2;
#[allow(unused)]
const SYMTAB_SECTION: u32 = 3;
#[allow(unused)]
const SYMTAB_TAG: u32 = 4;
const SYMTAB_TABLE: u32 = 5;

impl SymbolTable {
    /// Construct a new symbol table subsection encoder.
    pub fn new() -> Self {
        SymbolTable {
            bytes: vec![],
            num_added: 0,
        }
    }

    /// Define a function symbol in this symbol table.
    ///
    /// The `name` must be omitted if `index` references an imported table and
    /// the `WASM_SYM_EXPLICIT_NAME` flag is not set.
    pub fn function(&mut self, flags: u32, index: u32, name: Option<&str>) -> &mut Self {
        SYMTAB_FUNCTION.encode(&mut self.bytes);
        flags.encode(&mut self.bytes);
        index.encode(&mut self.bytes);
        if let Some(name) = name {
            name.encode(&mut self.bytes);
        }
        self.num_added += 1;
        self
    }

    /// Define a global symbol in this symbol table.
    ///
    /// The `name` must be omitted if `index` references an imported table and
    /// the `WASM_SYM_EXPLICIT_NAME` flag is not set.
    pub fn global(&mut self, flags: u32, index: u32, name: Option<&str>) -> &mut Self {
        SYMTAB_GLOBAL.encode(&mut self.bytes);
        flags.encode(&mut self.bytes);
        index.encode(&mut self.bytes);
        if let Some(name) = name {
            name.encode(&mut self.bytes);
        }
        self.num_added += 1;
        self
    }

    // TODO: tags

    /// Define a table symbol in this symbol table.
    ///
    /// The `name` must be omitted if `index` references an imported table and
    /// the `WASM_SYM_EXPLICIT_NAME` flag is not set.
    pub fn table(&mut self, flags: u32, index: u32, name: Option<&str>) -> &mut Self {
        SYMTAB_TABLE.encode(&mut self.bytes);
        flags.encode(&mut self.bytes);
        index.encode(&mut self.bytes);
        if let Some(name) = name {
            name.encode(&mut self.bytes);
        }
        self.num_added += 1;
        self
    }

    /// Add a data symbol to this symbol table.
    pub fn data(
        &mut self,
        flags: u32,
        name: &str,
        definition: Option<DataSymbolDefinition>,
    ) -> &mut Self {
        SYMTAB_DATA.encode(&mut self.bytes);
        flags.encode(&mut self.bytes);
        name.encode(&mut self.bytes);
        if let Some(def) = definition {
            def.index.encode(&mut self.bytes);
            def.offset.encode(&mut self.bytes);
            def.size.encode(&mut self.bytes);
        }
        self.num_added += 1;
        self
    }

    // TODO: sections

    /// This is a weak symbol.
    ///
    /// This flag is mutually exclusive with `WASM_SYM_BINDING_LOCAL`.
    ///
    /// When linking multiple modules defining the same symbol, all weak
    /// definitions are discarded if any strong definitions exist; then if
    /// multiple weak definitions exist all but one (unspecified) are discarded;
    /// and finally it is an error if more than one definition remains.
    pub const WASM_SYM_BINDING_WEAK: u32 = 0x1;

    /// This is a local symbol.
    ///
    /// This flag is mutually exclusive with `WASM_SYM_BINDING_WEAK`.
    ///
    /// Local symbols are not to be exported, or linked to other
    /// modules/sections. The names of all non-local symbols must be unique, but
    /// the names of local symbols are not considered for uniqueness. A local
    /// function or global symbol cannot reference an import.
    pub const WASM_SYM_BINDING_LOCAL: u32 = 0x02;

    /// This is a hidden symbol.
    ///
    /// Hidden symbols are not to be exported when performing the final link,
    /// but may be linked to other modules.
    pub const WASM_SYM_VISIBILITY_HIDDEN: u32 = 0x04;

    /// This symbol is not defined.
    ///
    /// For non-data symbols, this must match whether the symbol is an import or
    /// is defined; for data symbols, determines whether a segment is specified.
    pub const WASM_SYM_UNDEFINED: u32 = 0x10;

    /// This symbol is intended to be exported from the wasm module to the host
    /// environment.
    ///
    /// This differs from the visibility flags in that it effects the static
    /// linker.
    pub const WASM_SYM_EXPORTED: u32 = 0x20;

    /// This symbol uses an explicit symbol name, rather than reusing the name
    /// from a wasm import.
    ///
    /// This allows it to remap imports from foreign WebAssembly modules into
    /// local symbols with different names.
    pub const WASM_SYM_EXPLICIT_NAME: u32 = 0x40;

    /// This symbol is intended to be included in the linker output, regardless
    /// of whether it is used by the program.
    pub const WASM_SYM_NO_STRIP: u32 = 0x80;
}

impl Encode for SymbolTable {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.push(WASM_SYMBOL_TABLE);
        encode_section(sink, self.num_added, &self.bytes);
    }
}

/// The definition of a data symbol within a symbol table.
#[derive(Clone, Debug)]
pub struct DataSymbolDefinition {
    /// The index of the data segment that this symbol is in.
    pub index: u32,
    /// The offset of this symbol within its segment.
    pub offset: u32,
    /// The byte size (which can be zero) of this data symbol.
    ///
    /// Note that `offset + size` must be less than or equal to the segment's
    /// size.
    pub size: u32,
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/memories.rs

Source (jump to first uncovered line)
use crate::{encode_section, Encode, Section, SectionId};

/// An encoder for the memory section.
///
/// Memory sections are only supported for modules.
///
/// # Example
///
/// ```
/// use wasm_encoder::{Module, MemorySection, MemoryType};
///
/// let mut memories = MemorySection::new();
/// memories.memory(MemoryType {
///     minimum: 1,
///     maximum: None,
///     memory64: false,
///     shared: false,
///     page_size_log2: None,
/// });
///
/// let mut module = Module::new();
/// module.section(&memories);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Default, Debug)]
pub struct MemorySection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl MemorySection {
    /// Create a new memory section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of memories in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define a memory.
    pub fn memory(&mut self, memory_type: MemoryType) -> &mut Self {
        memory_type.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for MemorySection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for MemorySection {
    fn id(&self) -> u8 {
        SectionId::Memory.into()
    }
}

/// A memory's type.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub struct MemoryType {
    /// Minimum size, in pages, of this memory
    pub minimum: u64,
    /// Maximum size, in pages, of this memory
    pub maximum: Option<u64>,
    /// Whether or not this is a 64-bit memory.
    pub memory64: bool,
    /// Whether or not this memory is shared.
    pub shared: bool,
    /// The log base 2 of a custom page size for this memory.
    ///
    /// The default page size for Wasm memories is 64KiB, i.e. 2<sup>16</sup> or
    /// `65536`.
    ///
    /// After the introduction of [the custom-page-sizes
    /// proposal](https://github.com/WebAssembly/custom-page-sizes), Wasm can
    /// customize the page size. It must be a power of two that is less than or
    /// equal to 64KiB. Attempting to encode an invalid page size may panic.
    pub page_size_log2: Option<u32>,
}

impl Encode for MemoryType {
    fn encode(&self, sink: &mut Vec<u8>) {
        let mut flags = 0;
        if self.maximum.is_some() {
            flags |= 0b0001;
        }
        if self.shared {
            flags |= 0b0010;
        }
        if self.memory64 {
            flags |= 0b0100;
        }
        if self.page_size_log2.is_some() {
            flags |= 0b1000;
        }
        sink.push(flags);
        self.minimum.encode(sink);
        if let Some(max) = self.maximum {
            max.encode(sink);
        }
        if let Some(p) = self.page_size_log2 {
            p.encode(sink);
        }
    }
}

#[cfg(feature = "wasmparser")]
impl From<wasmparser::MemoryType> for MemoryType {
    fn from(memory_ty: wasmparser::MemoryType) -> Self {
        MemoryType {
            minimum: memory_ty.initial,
            maximum: memory_ty.maximum,
            memory64: memory_ty.memory64,
            shared: memory_ty.shared,
            page_size_log2: memory_ty.page_size_log2,
        }
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/names.rs

Source (jump to first uncovered line)
use std::borrow::Cow;

use crate::{encoding_size, CustomSection, Encode, Section, SectionId};

/// An encoder for the custom `name` section.
///
/// # Example
///
/// ```
/// use wasm_encoder::{Module, NameSection, NameMap};
///
/// let mut names = NameSection::new();
/// names.module("the module name");
///
/// let mut function_names = NameMap::new();
/// function_names.append(0, "name of function 0");
/// function_names.append(1, "a better function");
/// function_names.append(3, "the best function");
/// names.functions(&function_names);
///
/// let mut module = Module::new();
/// module.section(&names);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct NameSection {
    bytes: Vec<u8>,
}

enum Subsection {
    // Currently specified in the wasm spec's appendix
    Module = 0,
    Function = 1,
    Local = 2,

    // specified as part of the extended name section proposal
    //
    // https://github.com/WebAssembly/extended-name-section/blob/main/proposals/extended-name-section/Overview.md
    Label = 3,
    Type = 4,
    Table = 5,
    Memory = 6,
    Global = 7,
    Element = 8,
    Data = 9,

    // https://github.com/WebAssembly/gc/issues/193
    Field = 10,

    // https://github.com/WebAssembly/exception-handling/pull/213
    Tag = 11,
}

impl NameSection {
    /// Creates a new blank `name` custom section.
    pub fn new() -> Self {
        Self::default()
    }

    /// Appends a module name subsection to this section.
    ///
    /// This will indicate that the name of the entire module should be the
    /// `name` specified. Note that this should be encoded first before other
    /// subsections.
    pub fn module(&mut self, name: &str) {
        let len = encoding_size(u32::try_from(name.len()).unwrap());
        self.subsection_header(Subsection::Module, len + name.len());
        name.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of all functions in this wasm module.
    ///
    /// Function names are declared in the `names` map provided where the index
    /// in the map corresponds to the wasm index of the function. This section
    /// should come after the module name subsection (if present) and before the
    /// locals subsection (if present).
    pub fn functions(&mut self, names: &NameMap) {
        self.subsection_header(Subsection::Function, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of locals within functions in this
    /// wasm module.
    ///
    /// This section should come after the function name subsection (if present)
    /// and before the labels subsection (if present).
    pub fn locals(&mut self, names: &IndirectNameMap) {
        self.subsection_header(Subsection::Local, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of labels within functions in this
    /// wasm module.
    ///
    /// This section should come after the local name subsection (if present)
    /// and before the type subsection (if present).
    pub fn labels(&mut self, names: &IndirectNameMap) {
        self.subsection_header(Subsection::Label, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of all types in this wasm module.
    ///
    /// This section should come after the label name subsection (if present)
    /// and before the table subsection (if present).
    pub fn types(&mut self, names: &NameMap) {
        self.subsection_header(Subsection::Type, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of all tables in this wasm module.
    ///
    /// This section should come after the type name subsection (if present)
    /// and before the memory subsection (if present).
    pub fn tables(&mut self, names: &NameMap) {
        self.subsection_header(Subsection::Table, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of all memories in this wasm module.
    ///
    /// This section should come after the table name subsection (if present)
    /// and before the global subsection (if present).
    pub fn memories(&mut self, names: &NameMap) {
        self.subsection_header(Subsection::Memory, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of all globals in this wasm module.
    ///
    /// This section should come after the memory name subsection (if present)
    /// and before the element subsection (if present).
    pub fn globals(&mut self, names: &NameMap) {
        self.subsection_header(Subsection::Global, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of all elements in this wasm module.
    ///
    /// This section should come after the global name subsection (if present)
    /// and before the data subsection (if present).
    pub fn elements(&mut self, names: &NameMap) {
        self.subsection_header(Subsection::Element, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of all data in this wasm module.
    ///
    /// This section should come after the element name subsection (if present)
    /// and before the field subsection (if present).
    pub fn data(&mut self, names: &NameMap) {
        self.subsection_header(Subsection::Data, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of all tags in this wasm module.
    ///
    /// This section should come after the data name subsection (if present).
    pub fn tag(&mut self, names: &NameMap) {
        self.subsection_header(Subsection::Tag, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of fields within types in this
    /// wasm module.
    ///
    /// This section should come after the data name subsection (if present)
    /// and before the tag subsection (if present).
    pub fn fields(&mut self, names: &IndirectNameMap) {
        self.subsection_header(Subsection::Field, names.size());
        names.encode(&mut self.bytes);
    }

    /// Appends a subsection for the names of all tags in this wasm module.
    ///
    /// This section should come after the field name subsection (if present).
    pub fn tags(&mut self, names: &NameMap) {
        self.subsection_header(Subsection::Tag, names.size());
        names.encode(&mut self.bytes);
    }

    fn subsection_header(&mut self, id: Subsection, len: usize) {
        self.bytes.push(id as u8);
        len.encode(&mut self.bytes);
    }

    /// View the encoded section as a CustomSection.
    pub fn as_custom<'a>(&'a self) -> CustomSection<'a> {
        CustomSection {
            name: "name".into(),
            data: Cow::Borrowed(&self.bytes),
        }
    }
}

impl Encode for NameSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.as_custom().encode(sink);
    }
}

impl Section for NameSection {
    fn id(&self) -> u8 {
        SectionId::Custom.into()
    }
}

/// A map used to name items in a wasm module, organized by naming each
/// individual index.
///
/// This is used in conjunction with [`NameSection::functions`] and simlar
/// methods.
#[derive(Clone, Debug, Default)]
pub struct NameMap {
    bytes: Vec<u8>,
    count: u32,
}

impl NameMap {
    /// Creates a new empty `NameMap`.
    pub fn new() -> NameMap {
        NameMap {
            bytes: vec![],
            count: 0,
        }
    }

    /// Adds a an entry where the item at `idx` has the `name` specified.
    ///
    /// Note that indices should be appended in ascending order of the index
    /// value. Each index may only be named once, but not all indices must be
    /// named (e.g. `0 foo; 1 bar; 7 qux` is valid but `0 foo; 0 bar` is not).
    /// Names do not have to be unique (e.g. `0 foo; 1 foo; 2 foo` is valid).
    pub fn append(&mut self, idx: u32, name: &str) {
        idx.encode(&mut self.bytes);
        name.encode(&mut self.bytes);
        self.count += 1;
    }

    pub(crate) fn size(&self) -> usize {
        encoding_size(self.count) + self.bytes.len()
    }

    /// Returns whether no names have been added to this map.
    pub fn is_empty(&self) -> bool {
        self.count == 0
    }
}

impl Encode for NameMap {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.count.encode(sink);
        sink.extend(&self.bytes);
    }
}

/// A map used to describe names with two levels of indirection, as opposed to a
/// [`NameMap`] which has one level of indirection.
///
/// This naming map is used with [`NameSection::locals`], for example.
#[derive(Clone, Debug, Default)]
pub struct IndirectNameMap {
    bytes: Vec<u8>,
    count: u32,
}

impl IndirectNameMap {
    /// Creates a new empty name map.
    pub fn new() -> IndirectNameMap {
        IndirectNameMap {
            bytes: vec![],
            count: 0,
        }
    }

    /// Adds a new entry where the item at `idx` has sub-items named within
    /// `names` as specified.
    ///
    /// For example if this is describing local names then `idx` is a function
    /// index where the indexes within `names` are local indices.
    pub fn append(&mut self, idx: u32, names: &NameMap) {
        idx.encode(&mut self.bytes);
        names.encode(&mut self.bytes);
        self.count += 1;
    }

    fn size(&self) -> usize {
        encoding_size(self.count) + self.bytes.len()
    }
}

impl Encode for IndirectNameMap {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.count.encode(sink);
        sink.extend(&self.bytes);
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/producers.rs

Source (jump to first uncovered line)
use std::borrow::Cow;

use crate::{CustomSection, Encode, Section, SectionId};

/// An encoder for the [producers custom
/// section](https://github.com/WebAssembly/tool-conventions/blob/main/ProducersSection.md).
///
/// This section is a non-standard convention that is supported by many toolchains.
///
/// # Example
///
/// ```
/// use wasm_encoder::{ProducersSection, ProducersField, Module};
///
/// // Create a new producers section.
/// let mut field = ProducersField::new();
/// field.value("clang", "14.0.4");
/// field.value("rustc", "1.66.1 (90743e729 2023-01-10)");
/// let mut producers = ProducersSection::new();
/// producers.field("processed-by", &field);
///
/// // Add the producers section to a new Wasm module and get the encoded bytes.
/// let mut module = Module::new();
/// module.section(&producers);
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Debug)]
pub struct ProducersSection {
    bytes: Vec<u8>,
    num_fields: u32,
}

impl ProducersSection {
    /// Construct an empty encoder for the producers custom section.
    pub fn new() -> Self {
        Self::default()
    }

    /// Add a field to the section. The spec recommends names for this section
    /// are "language", "processed-by", and "sdk".  Each field in section must
    /// have a unique name.
    pub fn field(&mut self, name: &str, values: &ProducersField) -> &mut Self {
        name.encode(&mut self.bytes);
        values.encode(&mut self.bytes);
        self.num_fields += 1;
        self
    }
}

impl Default for ProducersSection {
    fn default() -> Self {
        Self {
            bytes: Vec::new(),
            num_fields: 0,
        }
    }
}

impl Encode for ProducersSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        let mut data = Vec::new();
        self.num_fields.encode(&mut data);
        data.extend(&self.bytes);

        CustomSection {
            name: "producers".into(),
            data: Cow::Borrowed(&data),
        }
        .encode(sink);
    }
}

impl Section for ProducersSection {
    fn id(&self) -> u8 {
        SectionId::Custom.into()
    }
}

/// The value of a field in the producers custom section
#[derive(Clone, Debug)]
pub struct ProducersField {
    bytes: Vec<u8>,
    num_values: u32,
}

impl ProducersField {
    /// Construct an empty encoder for a producers field value
    pub fn new() -> Self {
        ProducersField::default()
    }

    /// Add a value to the field encoder. Each value in a field must have a
    /// unique name. If there is no sensible value for `version`, use the
    /// empty string.
    pub fn value(&mut self, name: &str, version: &str) -> &mut Self {
        name.encode(&mut self.bytes);
        version.encode(&mut self.bytes);
        self.num_values += 1;
        self
    }
}

impl Default for ProducersField {
    fn default() -> Self {
        Self {
            bytes: Vec::new(),
            num_values: 0,
        }
    }
}

impl Encode for ProducersField {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.num_values.encode(sink);
        sink.extend(&self.bytes);
    }
}

#[cfg(test)]
mod test {
    #[test]
    fn roundtrip_example() {
        use crate::{Module, ProducersField, ProducersSection};
        use wasmparser::{KnownCustom, Parser, Payload};

        // Create a new producers section.
        let mut field = ProducersField::new();
        field.value("clang", "14.0.4");
        field.value("rustc", "1.66.1");
        let mut producers = ProducersSection::new();
        producers.field("processed-by", &field);

        // Add the producers section to a new Wasm module and get the encoded bytes.
        let mut module = Module::new();
        module.section(&producers);
        let wasm_bytes = module.finish();

        let mut parser = Parser::new(0).parse_all(&wasm_bytes);
        let payload = parser
            .next()
            .expect("parser is not empty")
            .expect("element is a payload");
        match payload {
            Payload::Version { .. } => {}
            _ => panic!(""),
        }
        let payload = parser
            .next()
            .expect("parser is not empty")
            .expect("element is a payload");
        match payload {
            Payload::CustomSection(c) => {
                assert_eq!(c.name(), "producers");
                let mut section = match c.as_known() {
                    KnownCustom::Producers(s) => s.into_iter(),
                    _ => panic!("unknown custom section"),
                };
                let field = section
                    .next()
                    .expect("section has an element")
                    .expect("element is a producers field");
                assert_eq!(field.name, "processed-by");
                let mut values = field.values.into_iter();
                let value = values
                    .next()
                    .expect("values has an element")
                    .expect("element is a producers field value");
                assert_eq!(value.name, "clang");
                assert_eq!(value.version, "14.0.4");

                let value = values
                    .next()
                    .expect("values has another element")
                    .expect("element is a producers field value");
                assert_eq!(value.name, "rustc");
                assert_eq!(value.version, "1.66.1");
            }
            _ => panic!("unexpected payload"),
        }
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/start.rs

Source
use crate::{encoding_size, Encode, Section, SectionId};

/// An encoder for the start section of WebAssembly modules.
///
/// # Example
///
/// Note: this doesn't actually define the function at index 0, its type, or its
/// code body, so the resulting Wasm module will be invalid. See `TypeSection`,
/// `FunctionSection`, and `CodeSection` for details on how to generate those
/// things.
///
/// ```
/// use wasm_encoder::{Module, StartSection};
///
/// let start = StartSection { function_index: 0 };
///
/// let mut module = Module::new();
/// module.section(&start);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Copy, Debug)]
pub struct StartSection {
    /// The index of the start function.
    pub function_index: u32,
}

impl Encode for StartSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encoding_size(self.function_index).encode(sink);
        self.function_index.encode(sink);
    }
}

impl Section for StartSection {
    fn id(&self) -> u8 {
        SectionId::Start.into()
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/tables.rs

Source (jump to first uncovered line)
use crate::{encode_section, ConstExpr, Encode, RefType, Section, SectionId, ValType};

/// An encoder for the table section.
///
/// Table sections are only supported for modules.
///
/// # Example
///
/// ```
/// use wasm_encoder::{Module, TableSection, TableType, RefType};
///
/// let mut tables = TableSection::new();
/// tables.table(TableType {
///     element_type: RefType::FUNCREF,
///     minimum: 128,
///     maximum: None,
///     table64: false,
/// });
///
/// let mut module = Module::new();
/// module.section(&tables);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Default, Debug)]
pub struct TableSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl TableSection {
    /// Construct a new table section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of tables in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define a table.
    pub fn table(&mut self, table_type: TableType) -> &mut Self {
        table_type.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// Define a table with an explicit initialization expression.
    ///
    /// Note that this is part of the function-references proposal.
    pub fn table_with_init(&mut self, table_type: TableType, init: &ConstExpr) -> &mut Self {
        self.bytes.push(0x40);
        self.bytes.push(0x00);
        table_type.encode(&mut self.bytes);
        init.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for TableSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for TableSection {
    fn id(&self) -> u8 {
        SectionId::Table.into()
    }
}

/// A table's type.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub struct TableType {
    /// The table's element type.
    pub element_type: RefType,
    /// Whether or not this is a 64-bit table.
    pub table64: bool,
    /// Minimum size, in elements, of this table
    pub minimum: u64,
    /// Maximum size, in elements, of this table
    pub maximum: Option<u64>,
}

impl TableType {
    /// Returns the type used to index this table.
    pub fn index_type(&self) -> ValType {
        if self.table64 {
            ValType::I64
        } else {
            ValType::I32
        }
    }
}

impl Encode for TableType {
    fn encode(&self, sink: &mut Vec<u8>) {
        let mut flags = 0;
        if self.maximum.is_some() {
            flags |= 0b001;
        }
        if self.table64 {
            flags |= 0b100;
        }

        self.element_type.encode(sink);
        sink.push(flags);
        self.minimum.encode(sink);

        if let Some(max) = self.maximum {
            max.encode(sink);
        }
    }
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::TableType> for TableType {
    type Error = ();
    fn try_from(table_ty: wasmparser::TableType) -> Result<Self, Self::Error> {
        Ok(TableType {
            element_type: table_ty.element_type.try_into()?,
            minimum: table_ty.initial,
            maximum: table_ty.maximum,
            table64: table_ty.table64,
        })
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/tags.rs

Source (jump to first uncovered line)
use crate::{encode_section, Encode, Section, SectionId};

/// An encoder for the tag section.
///
/// # Example
///
/// ```
/// use wasm_encoder::{Module, TagSection, TagType, TagKind};
///
/// let mut tags = TagSection::new();
/// tags.tag(TagType {
///     kind: TagKind::Exception,
///     func_type_idx: 0,
/// });
///
/// let mut module = Module::new();
/// module.section(&tags);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Default, Debug)]
pub struct TagSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl TagSection {
    /// Create a new tag section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of tags in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define a tag.
    pub fn tag(&mut self, tag_type: TagType) -> &mut Self {
        tag_type.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }
}

impl Encode for TagSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for TagSection {
    fn id(&self) -> u8 {
        SectionId::Tag.into()
    }
}

/// Represents a tag kind.
#[repr(u8)]
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum TagKind {
    /// The tag is an exception type.
    Exception = 0x0,
}

#[cfg(feature = "wasmparser")]
impl From<wasmparser::TagKind> for TagKind {
    fn from(kind: wasmparser::TagKind) -> Self {
        match kind {
            wasmparser::TagKind::Exception => TagKind::Exception,
        }
    }
}

/// A tag's type.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct TagType {
    /// The kind of tag
    pub kind: TagKind,
    /// The function type this tag uses
    pub func_type_idx: u32,
}

impl Encode for TagType {
    fn encode(&self, sink: &mut Vec<u8>) {
        sink.push(self.kind as u8);
        self.func_type_idx.encode(sink);
    }
}

#[cfg(feature = "wasmparser")]
impl From<wasmparser::TagType> for TagType {
    fn from(tag_ty: wasmparser::TagType) -> Self {
        TagType {
            kind: tag_ty.kind.into(),
            func_type_idx: tag_ty.func_type_idx,
        }
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/core/types.rs

Source (jump to first uncovered line)
use crate::{encode_section, Encode, Section, SectionId};

/// Represents a subtype of possible other types in a WebAssembly module.
#[derive(Debug, Clone)]
pub struct SubType {
    /// Is the subtype final.
    pub is_final: bool,
    /// The list of supertype indexes. As of GC MVP, there can be at most one supertype.
    pub supertype_idx: Option<u32>,
    /// The composite type of the subtype.
    pub composite_type: CompositeType,
}

impl Encode for SubType {
    fn encode(&self, sink: &mut Vec<u8>) {
        // We only need to emit a prefix byte before the actual composite type
        // when either the type is not final or it has a declared super type.
        if self.supertype_idx.is_some() || !self.is_final {
            sink.push(if self.is_final { 0x4f } else { 0x50 });
            self.supertype_idx.encode(sink);
        }
        self.composite_type.encode(sink);
    }
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::SubType> for SubType {
    type Error = ();

    fn try_from(sub_ty: wasmparser::SubType) -> Result<Self, Self::Error> {
        Ok(SubType {
            is_final: sub_ty.is_final,
            supertype_idx: sub_ty
                .supertype_idx
                .map(|i| i.as_module_index().ok_or(()))
                .transpose()?,
            composite_type: sub_ty.composite_type.try_into()?,
        })
    }
}

/// Represents a composite type in a WebAssembly module.
#[derive(Debug, Clone)]
pub enum CompositeType {
    /// The type is for a function.
    Func(FuncType),
    /// The type is for an array.
    Array(ArrayType),
    /// The type is for a struct.
    Struct(StructType),
}

impl Encode for CompositeType {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            CompositeType::Func(ty) => TypeSection::encode_function(
                sink,
                ty.params().iter().copied(),
                ty.results().iter().copied(),
            ),
            CompositeType::Array(ArrayType(ty)) => {
                TypeSection::encode_array(sink, &ty.element_type, ty.mutable)
            }
            CompositeType::Struct(ty) => {
                TypeSection::encode_struct(sink, ty.fields.iter().cloned())
            }
        }
    }
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::CompositeType> for CompositeType {
    type Error = ();
    fn try_from(composite_ty: wasmparser::CompositeType) -> Result<Self, Self::Error> {
        Ok(match composite_ty {
            wasmparser::CompositeType::Func(f) => CompositeType::Func(f.try_into()?),
            wasmparser::CompositeType::Array(a) => CompositeType::Array(a.try_into()?),
            wasmparser::CompositeType::Struct(s) => CompositeType::Struct(s.try_into()?),
        })
    }
}

/// Represents a type of a function in a WebAssembly module.
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct FuncType {
    /// The combined parameters and result types.
    params_results: Box<[ValType]>,
    /// The number of parameter types.
    len_params: usize,
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::FuncType> for FuncType {
    type Error = ();
    fn try_from(func_ty: wasmparser::FuncType) -> Result<Self, Self::Error> {
        let mut buf = Vec::with_capacity(func_ty.params().len() + func_ty.results().len());
        for ty in func_ty.params().iter().chain(func_ty.results()).copied() {
            buf.push(ty.try_into()?);
        }
        Ok(FuncType::from_parts(buf.into(), func_ty.params().len()))
    }
}

/// Represents a type of an array in a WebAssembly module.
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
pub struct ArrayType(pub FieldType);

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::ArrayType> for ArrayType {
    type Error = ();
    fn try_from(array_ty: wasmparser::ArrayType) -> Result<Self, Self::Error> {
        Ok(ArrayType(array_ty.0.try_into()?))
    }
}

/// Represents a type of a struct in a WebAssembly module.
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct StructType {
    /// Struct fields.
    pub fields: Box<[FieldType]>,
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::StructType> for StructType {
    type Error = ();
    fn try_from(struct_ty: wasmparser::StructType) -> Result<Self, Self::Error> {
        Ok(StructType {
            fields: struct_ty
                .fields
                .iter()
                .cloned()
                .map(TryInto::try_into)
                .collect::<Result<_, _>>()?,
        })
    }
}

/// Field type in composite types (structs, arrays).
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
pub struct FieldType {
    /// Storage type of the field.
    pub element_type: StorageType,
    /// Is the field mutable.
    pub mutable: bool,
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::FieldType> for FieldType {
    type Error = ();
    fn try_from(field_ty: wasmparser::FieldType) -> Result<Self, Self::Error> {
        Ok(FieldType {
            element_type: field_ty.element_type.try_into()?,
            mutable: field_ty.mutable,
        })
    }
}

/// Storage type for composite type fields.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
pub enum StorageType {
    /// The `i8` type.
    I8,
    /// The `i16` type.
    I16,
    /// A value type.
    Val(ValType),
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::StorageType> for StorageType {
    type Error = ();
    fn try_from(storage_ty: wasmparser::StorageType) -> Result<Self, Self::Error> {
        Ok(match storage_ty {
            wasmparser::StorageType::I8 => StorageType::I8,
            wasmparser::StorageType::I16 => StorageType::I16,
            wasmparser::StorageType::Val(v) => StorageType::Val(v.try_into()?),
        })
    }
}

impl StorageType {
    /// Is this storage type defaultable?
    pub fn is_defaultable(&self) -> bool {
        self.unpack().is_defaultable()
    }

    /// Unpack this storage type into a value type.
    pub fn unpack(&self) -> ValType {
        match self {
            StorageType::I8 | StorageType::I16 => ValType::I32,
            StorageType::Val(v) => *v,
        }
    }
}

/// The type of a core WebAssembly value.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
pub enum ValType {
    /// The `i32` type.
    I32,
    /// The `i64` type.
    I64,
    /// The `f32` type.
    F32,
    /// The `f64` type.
    F64,
    /// The `v128` type.
    ///
    /// Part of the SIMD proposal.
    V128,
    /// A reference type.
    ///
    /// The `funcref` and `externref` type fall into this category and the full
    /// generalization here is due to the implementation of the
    /// function-references proposal.
    Ref(RefType),
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::ValType> for ValType {
    type Error = ();
    fn try_from(val_ty: wasmparser::ValType) -> Result<Self, Self::Error> {
        Ok(match val_ty {
            wasmparser::ValType::I32 => ValType::I32,
            wasmparser::ValType::I64 => ValType::I64,
            wasmparser::ValType::F32 => ValType::F32,
            wasmparser::ValType::F64 => ValType::F64,
            wasmparser::ValType::V128 => ValType::V128,
            wasmparser::ValType::Ref(r) => ValType::Ref(r.try_into()?),
        })
    }
}

impl ValType {
    /// Is this a numeric value type?
    pub fn is_numeric(&self) -> bool {
        match self {
            ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 => true,
            ValType::V128 | ValType::Ref(_) => false,
        }
    }

    /// Is this a vector type?
    pub fn is_vector(&self) -> bool {
        match self {
            ValType::V128 => true,
            ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 | ValType::Ref(_) => false,
        }
    }

    /// Is this a reference type?
    pub fn is_reference(&self) -> bool {
        match self {
            ValType::Ref(_) => true,
            ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 | ValType::V128 => false,
        }
    }
}

impl FuncType {
    /// Creates a new [`FuncType`] from the given `params` and `results`.
    pub fn new<P, R>(params: P, results: R) -> Self
    where
        P: IntoIterator<Item = ValType>,
        R: IntoIterator<Item = ValType>,
    {
        let mut buffer = params.into_iter().collect::<Vec<_>>();
        let len_params = buffer.len();
        buffer.extend(results);
        Self::from_parts(buffer.into(), len_params)
    }

    #[inline]
    pub(crate) fn from_parts(params_results: Box<[ValType]>, len_params: usize) -> Self {
        Self {
            params_results,
            len_params,
        }
    }

    /// Returns a shared slice to the parameter types of the [`FuncType`].
    #[inline]
    pub fn params(&self) -> &[ValType] {
        &self.params_results[..self.len_params]
    }

    /// Returns a shared slice to the result types of the [`FuncType`].
    #[inline]
    pub fn results(&self) -> &[ValType] {
        &self.params_results[self.len_params..]
    }
}

impl ValType {
    /// Alias for the `funcref` type in WebAssembly
    pub const FUNCREF: ValType = ValType::Ref(RefType::FUNCREF);
    /// Alias for the `externref` type in WebAssembly
    pub const EXTERNREF: ValType = ValType::Ref(RefType::EXTERNREF);
    /// Alias for the `exnref` type in WebAssembly
    pub const EXNREF: ValType = ValType::Ref(RefType::EXNREF);

    /// Is this value defaultable?
    pub fn is_defaultable(&self) -> bool {
        match self {
            ValType::Ref(r) => r.nullable,
            ValType::I32 | ValType::I64 | ValType::F32 | ValType::F64 | ValType::V128 => true,
        }
    }
}

impl Encode for StorageType {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            StorageType::I8 => sink.push(0x78),
            StorageType::I16 => sink.push(0x77),
            StorageType::Val(vt) => vt.encode(sink),
        }
    }
}

impl Encode for ValType {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            ValType::I32 => sink.push(0x7F),
            ValType::I64 => sink.push(0x7E),
            ValType::F32 => sink.push(0x7D),
            ValType::F64 => sink.push(0x7C),
            ValType::V128 => sink.push(0x7B),
            ValType::Ref(rt) => rt.encode(sink),
        }
    }
}

/// A reference type.
///
/// This is largely part of the function references proposal for WebAssembly but
/// additionally is used by the `funcref` and `externref` types. The full
/// generality of this type is only exercised with function-references.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
#[allow(missing_docs)]
pub struct RefType {
    pub nullable: bool,
    pub heap_type: HeapType,
}

impl RefType {
    /// Alias for the `funcref` type in WebAssembly
    pub const FUNCREF: RefType = RefType {
        nullable: true,
        heap_type: HeapType::Func,
    };

    /// Alias for the `externref` type in WebAssembly
    pub const EXTERNREF: RefType = RefType {
        nullable: true,
        heap_type: HeapType::Extern,
    };

    /// Alias for the `exnref` type in WebAssembly
    pub const EXNREF: RefType = RefType {
        nullable: true,
        heap_type: HeapType::Exn,
    };
}

impl Encode for RefType {
    fn encode(&self, sink: &mut Vec<u8>) {
        if self.nullable {
            // Favor the original encodings of `funcref` and `externref` where
            // possible
            match self.heap_type {
                HeapType::Func => return sink.push(0x70),
                HeapType::Extern => return sink.push(0x6f),
                _ => {}
            }
        }

        if self.nullable {
            sink.push(0x63);
        } else {
            sink.push(0x64);
        }
        self.heap_type.encode(sink);
    }
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::RefType> for RefType {
    type Error = ();

    fn try_from(ref_type: wasmparser::RefType) -> Result<Self, Self::Error> {
        Ok(RefType {
            nullable: ref_type.is_nullable(),
            heap_type: ref_type.heap_type().try_into()?,
        })
    }
}

impl From<RefType> for ValType {
    fn from(ty: RefType) -> ValType {
        ValType::Ref(ty)
    }
}

/// Part of the function references proposal.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
pub enum HeapType {
    /// Untyped (any) function.
    Func,

    /// The abstract external heap type.
    Extern,

    /// The abstract `any` heap type.
    ///
    /// The common supertype (a.k.a. top) of all internal types.
    Any,

    /// The abstract `none` heap type.
    ///
    /// The common subtype (a.k.a. bottom) of all internal types.
    None,

    /// The abstract `noextern` heap type.
    ///
    /// The common subtype (a.k.a. bottom) of all external types.
    NoExtern,

    /// The abstract `nofunc` heap type.
    ///
    /// The common subtype (a.k.a. bottom) of all function types.
    NoFunc,

    /// The abstract `eq` heap type.
    ///
    /// The common supertype of all referenceable types on which comparison
    /// (ref.eq) is allowed.
    Eq,

    /// The abstract `struct` heap type.
    ///
    /// The common supertype of all struct types.
    Struct,

    /// The abstract `array` heap type.
    ///
    /// The common supertype of all array types.
    Array,

    /// The unboxed `i31` heap type.
    I31,

    /// The abstract `exception` heap type.
    Exn,

    /// The abstract `noexn` heap type.
    NoExn,

    /// A concrete Wasm-defined type at the given index.
    Concrete(u32),
}

impl Encode for HeapType {
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            HeapType::Func => sink.push(0x70),
            HeapType::Extern => sink.push(0x6F),
            HeapType::Any => sink.push(0x6E),
            HeapType::None => sink.push(0x71),
            HeapType::NoExtern => sink.push(0x72),
            HeapType::NoFunc => sink.push(0x73),
            HeapType::Eq => sink.push(0x6D),
            HeapType::Struct => sink.push(0x6B),
            HeapType::Array => sink.push(0x6A),
            HeapType::I31 => sink.push(0x6C),
            HeapType::Exn => sink.push(0x69),
            HeapType::NoExn => sink.push(0x74),
            // Note that this is encoded as a signed type rather than unsigned
            // as it's decoded as an s33
            HeapType::Concrete(i) => i64::from(*i).encode(sink),
        }
    }
}

#[cfg(feature = "wasmparser")]
impl TryFrom<wasmparser::HeapType> for HeapType {
    type Error = ();

    fn try_from(heap_type: wasmparser::HeapType) -> Result<Self, Self::Error> {
        Ok(match heap_type {
            wasmparser::HeapType::Concrete(i) => HeapType::Concrete(i.as_module_index().ok_or(())?),
            wasmparser::HeapType::Func => HeapType::Func,
            wasmparser::HeapType::Extern => HeapType::Extern,
            wasmparser::HeapType::Any => HeapType::Any,
            wasmparser::HeapType::None => HeapType::None,
            wasmparser::HeapType::NoExtern => HeapType::NoExtern,
            wasmparser::HeapType::NoFunc => HeapType::NoFunc,
            wasmparser::HeapType::Eq => HeapType::Eq,
            wasmparser::HeapType::Struct => HeapType::Struct,
            wasmparser::HeapType::Array => HeapType::Array,
            wasmparser::HeapType::I31 => HeapType::I31,
            wasmparser::HeapType::Exn => HeapType::Exn,
            wasmparser::HeapType::NoExn => HeapType::NoExn,
        })
    }
}

/// An encoder for the type section of WebAssembly modules.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Module, TypeSection, ValType};
///
/// let mut types = TypeSection::new();
///
/// types.function([ValType::I32, ValType::I32], [ValType::I64]);
///
/// let mut module = Module::new();
/// module.section(&types);
///
/// let bytes = module.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct TypeSection {
    bytes: Vec<u8>,
    num_added: u32,
}

impl TypeSection {
    /// Create a new module type section encoder.
    pub fn new() -> Self {
        Self::default()
    }

    /// The number of types in the section.
    pub fn len(&self) -> u32 {
        self.num_added
    }

    /// Determines if the section is empty.
    pub fn is_empty(&self) -> bool {
        self.num_added == 0
    }

    /// Define a function type in this type section.
    pub fn function<P, R>(&mut self, params: P, results: R) -> &mut Self
    where
        P: IntoIterator<Item = ValType>,
        P::IntoIter: ExactSizeIterator,
        R: IntoIterator<Item = ValType>,
        R::IntoIter: ExactSizeIterator,
    {
        Self::encode_function(&mut self.bytes, params, results);
        self.num_added += 1;
        self
    }

    fn encode_function<P, R>(sink: &mut Vec<u8>, params: P, results: R)
    where
        P: IntoIterator<Item = ValType>,
        P::IntoIter: ExactSizeIterator,
        R: IntoIterator<Item = ValType>,
        R::IntoIter: ExactSizeIterator,
    {
        let params = params.into_iter();
        let results = results.into_iter();

        sink.push(0x60);
        params.len().encode(sink);
        params.for_each(|p| p.encode(sink));
        results.len().encode(sink);
        results.for_each(|p| p.encode(sink));
    }

    /// Define an array type in this type section.
    pub fn array(&mut self, ty: &StorageType, mutable: bool) -> &mut Self {
        Self::encode_array(&mut self.bytes, ty, mutable);
        self.num_added += 1;
        self
    }

    fn encode_array(sink: &mut Vec<u8>, ty: &StorageType, mutable: bool) {
        sink.push(0x5e);
        Self::encode_field(sink, ty, mutable);
    }

    fn encode_field(sink: &mut Vec<u8>, ty: &StorageType, mutable: bool) {
        ty.encode(sink);
        sink.push(mutable as u8);
    }

    /// Define a struct type in this type section.
    pub fn struct_<F>(&mut self, fields: F) -> &mut Self
    where
        F: IntoIterator<Item = FieldType>,
        F::IntoIter: ExactSizeIterator,
    {
        Self::encode_struct(&mut self.bytes, fields);
        self.num_added += 1;
        self
    }

    fn encode_struct<F>(sink: &mut Vec<u8>, fields: F)
    where
        F: IntoIterator<Item = FieldType>,
        F::IntoIter: ExactSizeIterator,
    {
        let fields = fields.into_iter();
        sink.push(0x5f);
        fields.len().encode(sink);
        for f in fields {
            Self::encode_field(sink, &f.element_type, f.mutable);
        }
    }

    /// Define an explicit subtype in this type section.
    pub fn subtype(&mut self, ty: &SubType) -> &mut Self {
        ty.encode(&mut self.bytes);
        self.num_added += 1;
        self
    }

    /// Define an explicit recursion group in this type section.
    pub fn rec<T>(&mut self, types: T) -> &mut Self
    where
        T: IntoIterator<Item = SubType>,
        T::IntoIter: ExactSizeIterator,
    {
        let types = types.into_iter();
        self.bytes.push(0x4e);
        types.len().encode(&mut self.bytes);
        types.for_each(|t| t.encode(&mut self.bytes));
        self.num_added += 1;
        self
    }
}

impl Encode for TypeSection {
    fn encode(&self, sink: &mut Vec<u8>) {
        encode_section(sink, self.num_added, &self.bytes);
    }
}

impl Section for TypeSection {
    fn id(&self) -> u8 {
        SectionId::Type.into()
    }
}

#[cfg(test)]
mod tests {
    use wasmparser::WasmFeatures;

    use super::*;
    use crate::Module;

    #[test]
    fn func_types_dont_require_wasm_gc() {
        let mut types = TypeSection::new();
        types.subtype(&SubType {
            is_final: true,
            supertype_idx: None,
            composite_type: CompositeType::Func(FuncType::new([], [])),
        });

        let mut module = Module::new();
        module.section(&types);
        let wasm_bytes = module.finish();

        let mut validator =
            wasmparser::Validator::new_with_features(WasmFeatures::default() & !WasmFeatures::GC);

        validator.validate_all(&wasm_bytes).expect(
            "Encoding pre Wasm GC type should not accidentally use Wasm GC specific encoding",
        );
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/lib.rs

Source (jump to first uncovered line)
//! A WebAssembly encoder.
//!
//! The main builder is the [`Module`]. You can build a section with a
//! section-specific builder, like [`TypeSection`] or [`ImportSection`], and
//! then add it to the module with [`Module::section`]. When you are finished
//! building the module, call either [`Module::as_slice`] or [`Module::finish`]
//! to get the encoded bytes. The former gives a shared reference to the
//! underlying bytes as a slice, while the latter gives you ownership of them as
//! a vector.
//!
//! # Example
//!
//! If we wanted to build this module:
//!
//! ```wasm
//! (module
//!   (type (func (param i32 i32) (result i32)))
//!   (func (type 0)
//!     local.get 0
//!     local.get 1
//!     i32.add)
//!   (export "f" (func 0)))
//! ```
//!
//! then we would do this:
//!
//! ```
//! use wasm_encoder::{
//!     CodeSection, ExportKind, ExportSection, Function, FunctionSection, Instruction,
//!     Module, TypeSection, ValType,
//! };
//!
//! let mut module = Module::new();
//!
//! // Encode the type section.
//! let mut types = TypeSection::new();
//! let params = vec![ValType::I32, ValType::I32];
//! let results = vec![ValType::I32];
//! types.function(params, results);
//! module.section(&types);
//!
//! // Encode the function section.
//! let mut functions = FunctionSection::new();
//! let type_index = 0;
//! functions.function(type_index);
//! module.section(&functions);
//!
//! // Encode the export section.
//! let mut exports = ExportSection::new();
//! exports.export("f", ExportKind::Func, 0);
//! module.section(&exports);
//!
//! // Encode the code section.
//! let mut codes = CodeSection::new();
//! let locals = vec![];
//! let mut f = Function::new(locals);
//! f.instruction(&Instruction::LocalGet(0));
//! f.instruction(&Instruction::LocalGet(1));
//! f.instruction(&Instruction::I32Add);
//! f.instruction(&Instruction::End);
//! codes.function(&f);
//! module.section(&codes);
//!
//! // Extract the encoded Wasm bytes for this module.
//! let wasm_bytes = module.finish();
//!
//! // We generated a valid Wasm module!
//! assert!(wasmparser::validate(&wasm_bytes).is_ok());
//! ```

#![deny(missing_docs, missing_debug_implementations)]

mod component;
mod core;
mod raw;

pub use self::component::*;
pub use self::core::*;
pub use self::raw::*;

/// Implemented by types that can be encoded into a byte sink.
pub trait Encode {
    /// Encode the type into the given byte sink.
    fn encode(&self, sink: &mut Vec<u8>);
}

impl<T: Encode + ?Sized> Encode for &'_ T {
    fn encode(&self, sink: &mut Vec<u8>) {
        T::encode(self, sink)
    }
}

impl<T: Encode> Encode for [T] {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.len().encode(sink);
        for item in self {
            item.encode(sink);
        }
    }
}

impl Encode for [u8] {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.len().encode(sink);
        sink.extend(self);
    }
}

impl Encode for str {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.len().encode(sink);
        sink.extend_from_slice(self.as_bytes());
    }
}

impl Encode for usize {
    fn encode(&self, sink: &mut Vec<u8>) {
        assert!(*self <= u32::max_value() as usize);
        (*self as u32).encode(sink)
    }
}

impl Encode for u32 {
    fn encode(&self, sink: &mut Vec<u8>) {
        leb128::write::unsigned(sink, (*self).into()).unwrap();
    }
}

impl Encode for i32 {
    fn encode(&self, sink: &mut Vec<u8>) {
        leb128::write::signed(sink, (*self).into()).unwrap();
    }
}

impl Encode for u64 {
    fn encode(&self, sink: &mut Vec<u8>) {
        leb128::write::unsigned(sink, *self).unwrap();
    }
}

impl Encode for i64 {
    fn encode(&self, sink: &mut Vec<u8>) {
        leb128::write::signed(sink, *self).unwrap();
    }
}

impl Encode for f32 {
    fn encode(&self, sink: &mut Vec<u8>) {
        let bits = self.to_bits();
        sink.extend(bits.to_le_bytes())
    }
}

impl Encode for f64 {
    fn encode(&self, sink: &mut Vec<u8>) {
        let bits = self.to_bits();
        sink.extend(bits.to_le_bytes())
    }
}

fn encode_vec<T, V>(elements: V, sink: &mut Vec<u8>)
where
    T: Encode,
    V: IntoIterator<Item = T>,
    V::IntoIter: ExactSizeIterator,
{
    let elements = elements.into_iter();
    u32::try_from(elements.len()).unwrap().encode(sink);
    for x in elements {
        x.encode(sink);
    }
}

impl<T> Encode for Option<T>
where
    T: Encode,
{
    fn encode(&self, sink: &mut Vec<u8>) {
        match self {
            Some(v) => {
                sink.push(0x01);
                v.encode(sink);
            }
            None => sink.push(0x00),
        }
    }
}

fn encoding_size(n: u32) -> usize {
    let mut buf = [0u8; 5];
    leb128::write::unsigned(&mut &mut buf[..], n.into()).unwrap()
}

fn encode_section(sink: &mut Vec<u8>, count: u32, bytes: &[u8]) {
    (encoding_size(count) + bytes.len()).encode(sink);
    count.encode(sink);
    sink.extend(bytes);
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn it_encodes_an_empty_module() {
        let bytes = Module::new().finish();
        assert_eq!(bytes, [0x00, b'a', b's', b'm', 0x01, 0x00, 0x00, 0x00]);
    }

    #[test]
    fn it_encodes_an_empty_component() {
        let bytes = Component::new().finish();
        assert_eq!(bytes, [0x00, b'a', b's', b'm', 0x0d, 0x00, 0x01, 0x00]);
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-encoder-0.210.0/src/raw.rs

Source (jump to first uncovered line)
use crate::{ComponentSection, Encode, Section};

/// A section made up of uninterpreted, raw bytes.
///
/// Allows you to splat any data into a module or component.
#[derive(Clone, Copy, Debug)]
pub struct RawSection<'a> {
    /// The id for this section.
    pub id: u8,
    /// The raw data for this section.
    pub data: &'a [u8],
}

impl Encode for RawSection<'_> {
    fn encode(&self, sink: &mut Vec<u8>) {
        self.data.encode(sink);
    }
}

impl Section for RawSection<'_> {
    fn id(&self) -> u8 {
        self.id
    }
}

impl ComponentSection for RawSection<'_> {
    fn id(&self) -> u8 {
        self.id
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-smith-0.210.0/src/component.rs

Source (jump to first uncovered line)
//! Generation of Wasm
//! [components](https://github.com/WebAssembly/component-model).

// FIXME(#1000): component support in `wasm-smith` is a work in progress.
#![allow(unused_variables, dead_code)]

use crate::{arbitrary_loop, Config};
use arbitrary::{Arbitrary, Result, Unstructured};
use std::collections::BTreeMap;
use std::{
    collections::{HashMap, HashSet},
    rc::Rc,
};
use wasm_encoder::{
    ComponentTypeRef, ComponentValType, HeapType, PrimitiveValType, RefType, TypeBounds, ValType,
};

mod encode;

/// A pseudo-random WebAssembly [component].
///
/// Construct instances of this type with [the `Arbitrary`
/// trait](https://docs.rs/arbitrary/*/arbitrary/trait.Arbitrary.html).
///
/// [component]: https://github.com/WebAssembly/component-model/blob/ast-and-binary/design/MVP/Explainer.md
///
/// ## Configured Generated Components
///
/// The `Arbitrary` implementation uses the [`Config::default()`][crate::Config]
/// configuration. If you want to customize the shape of generated components,
/// create your own [`Config`][crate::Config] instance and pass it to
/// [`Component::new`][crate::Component::new].
#[derive(Debug)]
pub struct Component {
    sections: Vec<Section>,
}

/// A builder to create a component (and possibly a whole tree of nested
/// components).
///
/// Maintains a stack of components we are currently building, as well as
/// metadata about them. The split between `Component` and `ComponentBuilder` is
/// that the builder contains metadata that is purely used when generating
/// components and is unnecessary after we are done generating the structure of
/// the components and only need to encode an already-generated component to
/// bytes.
#[derive(Debug)]
struct ComponentBuilder {
    config: Config,

    // The set of core `valtype`s that we are configured to generate.
    core_valtypes: Vec<ValType>,

    // Stack of types scopes that are currently available.
    //
    // There is an entry in this stack for each component, but there can also be
    // additional entries for module/component/instance types, each of which
    // have their own scope.
    //
    // This stack is always non-empty and the last entry is always the current
    // scope.
    //
    // When a particular scope can alias outer types, it can alias from any
    // scope that is older than it (i.e. `types_scope[i]` can alias from
    // `types_scope[j]` when `j <= i`).
    types: Vec<TypesScope>,

    // The set of components we are currently building and their associated
    // metadata.
    components: Vec<ComponentContext>,

    // Whether we are in the final bits of generating this component and we just
    // need to ensure that the minimum number of entities configured have all
    // been generated. This changes the behavior of various
    // `arbitrary_<section>` methods to always fill in their minimums.
    fill_minimums: bool,

    // Our maximums for these entities are applied across the whole component
    // tree, not per-component.
    total_components: usize,
    total_modules: usize,
    total_instances: usize,
    total_values: usize,
}

#[derive(Debug, Clone)]
enum ComponentOrCoreFuncType {
    Component(Rc<FuncType>),
    Core(Rc<crate::core::FuncType>),
}

impl ComponentOrCoreFuncType {
    fn as_core(&self) -> &Rc<crate::core::FuncType> {
        match self {
            ComponentOrCoreFuncType::Core(t) => t,
            ComponentOrCoreFuncType::Component(_) => panic!("not a core func type"),
        }
    }

    fn as_component(&self) -> &Rc<FuncType> {
        match self {
            ComponentOrCoreFuncType::Core(_) => panic!("not a component func type"),
            ComponentOrCoreFuncType::Component(t) => t,
        }
    }
}

#[derive(Debug, Clone)]
enum ComponentOrCoreInstanceType {
    Component(Rc<InstanceType>),
    Core(BTreeMap<String, crate::core::EntityType>),
}

/// Metadata (e.g. contents of various index spaces) we keep track of on a
/// per-component basis.
#[derive(Debug)]
struct ComponentContext {
    // The actual component itself.
    component: Component,

    // The number of imports we have generated thus far.
    num_imports: usize,

    // The set of names of imports we've generated thus far.
    import_names: HashSet<String>,

    // The set of URLs of imports we've generated thus far.
    import_urls: HashSet<String>,

    // This component's function index space.
    funcs: Vec<ComponentOrCoreFuncType>,

    // Which entries in `funcs` are component functions?
    component_funcs: Vec<u32>,

    // Which entries in `component_funcs` are component functions that only use scalar
    // types?
    scalar_component_funcs: Vec<u32>,

    // Which entries in `funcs` are core Wasm functions?
    //
    // Note that a component can't import core functions, so these entries will
    // never point to a `Section::Import`.
    core_funcs: Vec<u32>,

    // This component's component index space.
    //
    // An indirect list of all directly-nested (not transitive) components
    // inside this component.
    //
    // Each entry is of the form `(i, j)` where `component.sections[i]` is
    // guaranteed to be either
    //
    // * a `Section::Component` and we are referencing the component defined in
    //   that section (in this case `j` must also be `0`, since a component
    //   section can only contain a single nested component), or
    //
    // * a `Section::Import` and we are referencing the `j`th import in that
    //   section, which is guaranteed to be a component import.
    components: Vec<(usize, usize)>,

    // This component's module index space.
    //
    // An indirect list of all directly-nested (not transitive) modules
    // inside this component.
    //
    // Each entry is of the form `(i, j)` where `component.sections[i]` is
    // guaranteed to be either
    //
    // * a `Section::Core` and we are referencing the module defined in that
    //   section (in this case `j` must also be `0`, since a core section can
    //   only contain a single nested module), or
    //
    // * a `Section::Import` and we are referencing the `j`th import in that
    //   section, which is guaranteed to be a module import.
    modules: Vec<(usize, usize)>,

    // This component's instance index space.
    instances: Vec<ComponentOrCoreInstanceType>,

    // This component's value index space.
    values: Vec<ComponentValType>,
}

impl ComponentContext {
    fn empty() -> Self {
        ComponentContext {
            component: Component::empty(),
            num_imports: 0,
            import_names: HashSet::default(),
            import_urls: HashSet::default(),
            funcs: vec![],
            component_funcs: vec![],
            scalar_component_funcs: vec![],
            core_funcs: vec![],
            components: vec![],
            modules: vec![],
            instances: vec![],
            values: vec![],
        }
    }

    fn num_modules(&self) -> usize {
        self.modules.len()
    }

    fn num_components(&self) -> usize {
        self.components.len()
    }

    fn num_instances(&self) -> usize {
        self.instances.len()
    }

    fn num_funcs(&self) -> usize {
        self.funcs.len()
    }

    fn num_values(&self) -> usize {
        self.values.len()
    }
}

#[derive(Debug, Default)]
struct TypesScope {
    // All core types in this scope, regardless of kind.
    core_types: Vec<Rc<CoreType>>,

    // The indices of all the entries in `core_types` that are core function types.
    core_func_types: Vec<u32>,

    // The indices of all the entries in `core_types` that are module types.
    module_types: Vec<u32>,

    // All component types in this index space, regardless of kind.
    types: Vec<Rc<Type>>,

    // The indices of all the entries in `types` that are defined value types.
    defined_types: Vec<u32>,

    // The indices of all the entries in `types` that are func types.
    func_types: Vec<u32>,

    // A map from function types to their indices in the types space.
    func_type_to_indices: HashMap<Rc<FuncType>, Vec<u32>>,

    // The indices of all the entries in `types` that are component types.
    component_types: Vec<u32>,

    // The indices of all the entries in `types` that are instance types.
    instance_types: Vec<u32>,
}

impl TypesScope {
    fn push(&mut self, ty: Rc<Type>) -> u32 {
        let ty_idx = u32::try_from(self.types.len()).unwrap();

        let kind_list = match &*ty {
            Type::Defined(_) => &mut self.defined_types,
            Type::Func(func_ty) => {
                self.func_type_to_indices
                    .entry(func_ty.clone())
                    .or_default()
                    .push(ty_idx);
                &mut self.func_types
            }
            Type::Component(_) => &mut self.component_types,
            Type::Instance(_) => &mut self.instance_types,
        };
        kind_list.push(ty_idx);

        self.types.push(ty);
        ty_idx
    }

    fn push_core(&mut self, ty: Rc<CoreType>) -> u32 {
        let ty_idx = u32::try_from(self.core_types.len()).unwrap();

        let kind_list = match &*ty {
            CoreType::Func(_) => &mut self.core_func_types,
            CoreType::Module(_) => &mut self.module_types,
        };
        kind_list.push(ty_idx);

        self.core_types.push(ty);
        ty_idx
    }

    fn get(&self, index: u32) -> &Rc<Type> {
        &self.types[index as usize]
    }

    fn get_core(&self, index: u32) -> &Rc<CoreType> {
        &self.core_types[index as usize]
    }

    fn get_func(&self, index: u32) -> &Rc<FuncType> {
        match &**self.get(index) {
            Type::Func(f) => f,
            _ => panic!("get_func on non-function type"),
        }
    }

    fn can_ref_type(&self) -> bool {
        // All component types and core module types may be referenced
        !self.types.is_empty() || !self.module_types.is_empty()
    }
}

impl<'a> Arbitrary<'a> for Component {
    fn arbitrary(u: &mut Unstructured<'a>) -> Result<Self> {
        Component::new(Config::default(), u)
    }
}

#[derive(Default)]
struct EntityCounts {
    globals: usize,
    tables: usize,
    memories: usize,
    tags: usize,
    funcs: usize,
}

impl Component {
    /// Construct a new `Component` using the given configuration.
    pub fn new(config: Config, u: &mut Unstructured) -> Result<Self> {
        let mut builder = ComponentBuilder::new(config);
        builder.build(u)
    }

    fn empty() -> Self {
        Component { sections: vec![] }
    }
}

#[must_use]
enum Step {
    Finished(Component),
    StillBuilding,
}

impl Step {
    fn unwrap_still_building(self) {
        match self {
            Step::Finished(_) => panic!(
                "`Step::unwrap_still_building` called on a `Step` that is not `StillBuilding`"
            ),
            Step::StillBuilding => {}
        }
    }
}

impl ComponentBuilder {
    fn new(config: Config) -> Self {
        ComponentBuilder {
            config,
            core_valtypes: vec![],
            types: vec![Default::default()],
            components: vec![ComponentContext::empty()],
            fill_minimums: false,
            total_components: 0,
            total_modules: 0,
            total_instances: 0,
            total_values: 0,
        }
    }

    fn build(&mut self, u: &mut Unstructured) -> Result<Component> {
        self.core_valtypes = crate::core::configured_valtypes(&self.config);

        let mut choices: Vec<fn(&mut ComponentBuilder, &mut Unstructured) -> Result<Step>> = vec![];

        loop {
            choices.clear();
            choices.push(Self::finish_component);

            // Only add any choice other than "finish what we've generated thus
            // far" when there is more arbitrary fuzzer data for us to consume.
            if !u.is_empty() {
                choices.push(Self::arbitrary_custom_section);

                // NB: we add each section as a choice even if we've already
                // generated our maximum number of entities in that section so that
                // we can exercise adding empty sections to the end of the module.
                choices.push(Self::arbitrary_core_type_section);
                choices.push(Self::arbitrary_type_section);
                choices.push(Self::arbitrary_import_section);
                choices.push(Self::arbitrary_canonical_section);

                if self.total_modules < self.config.max_modules {
                    choices.push(Self::arbitrary_core_module_section);
                }

                if self.components.len() < self.config.max_nesting_depth
                    && self.total_components < self.config.max_components
                {
                    choices.push(Self::arbitrary_component_section);
                }

                // FIXME(#1000)
                //
                // choices.push(Self::arbitrary_instance_section);
                // choices.push(Self::arbitrary_export_section);
                // choices.push(Self::arbitrary_start_section);
                // choices.push(Self::arbitrary_alias_section);
            }

            let f = u.choose(&choices)?;
            match f(self, u)? {
                Step::StillBuilding => {}
                Step::Finished(component) => {
                    if self.components.is_empty() {
                        // If we just finished the root component, then return it.
                        return Ok(component);
                    } else {
                        // Otherwise, add it as a nested component in the parent.
                        self.push_section(Section::Component(component));
                    }
                }
            }
        }
    }

    fn finish_component(&mut self, u: &mut Unstructured) -> Result<Step> {
        // Ensure we've generated all of our minimums.
        self.fill_minimums = true;
        {
            if self.current_type_scope().types.len() < self.config.min_types {
                self.arbitrary_type_section(u)?.unwrap_still_building();
            }
            if self.component().num_imports < self.config.min_imports {
                self.arbitrary_import_section(u)?.unwrap_still_building();
            }
            if self.component().funcs.len() < self.config.min_funcs {
                self.arbitrary_canonical_section(u)?.unwrap_still_building();
            }
        }
        self.fill_minimums = false;

        self.types
            .pop()
            .expect("should have a types scope for the component we are finishing");
        Ok(Step::Finished(self.components.pop().unwrap().component))
    }

    fn component(&self) -> &ComponentContext {
        self.components.last().unwrap()
    }

    fn component_mut(&mut self) -> &mut ComponentContext {
        self.components.last_mut().unwrap()
    }

    fn last_section(&self) -> Option<&Section> {
        self.component().component.sections.last()
    }

    fn last_section_mut(&mut self) -> Option<&mut Section> {
        self.component_mut().component.sections.last_mut()
    }

    fn push_section(&mut self, section: Section) {
        self.component_mut().component.sections.push(section);
    }

    fn ensure_section(
        &mut self,
        mut predicate: impl FnMut(&Section) -> bool,
        mut make_section: impl FnMut() -> Section,
    ) -> &mut Section {
        match self.last_section() {
            Some(sec) if predicate(sec) => {}
            _ => self.push_section(make_section()),
        }
        self.last_section_mut().unwrap()
    }

    fn arbitrary_custom_section(&mut self, u: &mut Unstructured) -> Result<Step> {
        self.push_section(Section::Custom(u.arbitrary()?));
        Ok(Step::StillBuilding)
    }

    fn push_type(&mut self, ty: Rc<Type>) -> u32 {
        match self.ensure_section(
            |s| matches!(s, Section::Type(_)),
            || Section::Type(TypeSection { types: vec![] }),
        ) {
            Section::Type(TypeSection { types }) => {
                types.push(ty.clone());
                self.current_type_scope_mut().push(ty)
            }
            _ => unreachable!(),
        }
    }

    fn push_core_type(&mut self, ty: Rc<CoreType>) -> u32 {
        match self.ensure_section(
            |s| matches!(s, Section::CoreType(_)),
            || Section::CoreType(CoreTypeSection { types: vec![] }),
        ) {
            Section::CoreType(CoreTypeSection { types }) => {
                types.push(ty.clone());
                self.current_type_scope_mut().push_core(ty)
            }
            _ => unreachable!(),
        }
    }

    fn arbitrary_core_type_section(&mut self, u: &mut Unstructured) -> Result<Step> {
        self.push_section(Section::CoreType(CoreTypeSection { types: vec![] }));

        let min = if self.fill_minimums {
            self.config
                .min_types
                .saturating_sub(self.current_type_scope().types.len())
        } else {
            0
        };

        let max = self.config.max_types - self.current_type_scope().types.len();

        arbitrary_loop(u, min, max, |u| {
            let mut type_fuel = self.config.max_type_size;
            let ty = self.arbitrary_core_type(u, &mut type_fuel)?;
            self.push_core_type(ty);
            Ok(true)
        })?;

        Ok(Step::StillBuilding)
    }

    fn arbitrary_core_type(
        &self,
        u: &mut Unstructured,
        type_fuel: &mut u32,
    ) -> Result<Rc<CoreType>> {
        *type_fuel = type_fuel.saturating_sub(1);
        if *type_fuel == 0 {
            return Ok(Rc::new(CoreType::Module(Rc::new(ModuleType::default()))));
        }

        let ty = match u.int_in_range::<u8>(0..=1)? {
            0 => CoreType::Func(arbitrary_func_type(
                u,
                &self.config,
                &self.core_valtypes,
                if self.config.multi_value_enabled {
                    None
                } else {
                    Some(1)
                },
                0,
            )?),
            1 => CoreType::Module(self.arbitrary_module_type(u, type_fuel)?),
            _ => unreachable!(),
        };
        Ok(Rc::new(ty))
    }

    fn arbitrary_type_section(&mut self, u: &mut Unstructured) -> Result<Step> {
        self.push_section(Section::Type(TypeSection { types: vec![] }));

        let min = if self.fill_minimums {
            self.config
                .min_types
                .saturating_sub(self.current_type_scope().types.len())
        } else {
            0
        };

        let max = self.config.max_types - self.current_type_scope().types.len();

        arbitrary_loop(u, min, max, |u| {
            let mut type_fuel = self.config.max_type_size;
            let ty = self.arbitrary_type(u, &mut type_fuel)?;
            self.push_type(ty);
            Ok(true)
        })?;

        Ok(Step::StillBuilding)
    }

    fn arbitrary_type_ref<'a>(
        &self,
        u: &mut Unstructured<'a>,
        for_import: bool,
        for_type_def: bool,
    ) -> Result<Option<ComponentTypeRef>> {
        let mut choices: Vec<fn(&Self, &mut Unstructured) -> Result<ComponentTypeRef>> = Vec::new();
        let scope = self.current_type_scope();

        if !scope.module_types.is_empty()
            && (for_type_def || !for_import || self.total_modules < self.config.max_modules)
        {
            choices.push(|me, u| {
                Ok(ComponentTypeRef::Module(
                    *u.choose(&me.current_type_scope().module_types)?,
                ))
            });
        }

        // Types cannot be imported currently
        if !for_import
            && !scope.types.is_empty()
            && (for_type_def || scope.types.len() < self.config.max_types)
        {
            choices.push(|me, u| {
                Ok(ComponentTypeRef::Type(TypeBounds::Eq(u.int_in_range(
                    0..=u32::try_from(me.current_type_scope().types.len() - 1).unwrap(),
                )?)))
            });
        }

        // TODO: wasm-smith needs to ensure that every arbitrary value gets used exactly once.
        //       until that time, don't import values
        // if for_type_def || !for_import || self.total_values < self.config.max_values() {
        //     choices.push(|me, u| Ok(ComponentTypeRef::Value(me.arbitrary_component_val_type(u)?)));
        // }

        if !scope.func_types.is_empty()
            && (for_type_def || !for_import || self.component().num_funcs() < self.config.max_funcs)
        {
            choices.push(|me, u| {
                Ok(ComponentTypeRef::Func(
                    *u.choose(&me.current_type_scope().func_types)?,
                ))
            });
        }

        if !scope.component_types.is_empty()
            && (for_type_def || !for_import || self.total_components < self.config.max_components)
        {
            choices.push(|me, u| {
                Ok(ComponentTypeRef::Component(
                    *u.choose(&me.current_type_scope().component_types)?,
                ))
            });
        }

        if !scope.instance_types.is_empty()
            && (for_type_def || !for_import || self.total_instances < self.config.max_instances)
        {
            choices.push(|me, u| {
                Ok(ComponentTypeRef::Instance(
                    *u.choose(&me.current_type_scope().instance_types)?,
                ))
            });
        }

        if choices.is_empty() {
            return Ok(None);
        }

        let f = u.choose(&choices)?;
        f(self, u).map(Option::Some)
    }

    fn arbitrary_type(&mut self, u: &mut Unstructured, type_fuel: &mut u32) -> Result<Rc<Type>> {
        *type_fuel = type_fuel.saturating_sub(1);
        if *type_fuel == 0 {
            return Ok(Rc::new(Type::Defined(
                self.arbitrary_defined_type(u, type_fuel)?,
            )));
        }

        let ty = match u.int_in_range::<u8>(0..=3)? {
            0 => Type::Defined(self.arbitrary_defined_type(u, type_fuel)?),
            1 => Type::Func(self.arbitrary_func_type(u, type_fuel)?),
            2 => Type::Component(self.arbitrary_component_type(u, type_fuel)?),
            3 => Type::Instance(self.arbitrary_instance_type(u, type_fuel)?),
            _ => unreachable!(),
        };
        Ok(Rc::new(ty))
    }

    fn arbitrary_module_type(
        &self,
        u: &mut Unstructured,
        type_fuel: &mut u32,
    ) -> Result<Rc<ModuleType>> {
        let mut defs = vec![];
        let mut has_memory = false;
        let mut has_canonical_abi_realloc = false;
        let mut has_canonical_abi_free = false;
        let mut types: Vec<Rc<crate::core::FuncType>> = vec![];
        let mut imports = HashMap::new();
        let mut exports = HashSet::new();
        let mut counts = EntityCounts::default();

        // Special case the canonical ABI functions since certain types can only
        // be passed across the component boundary if they exist and
        // randomly generating them is extremely unlikely.

        // `memory`
        if counts.memories < self.config.max_memories && u.ratio::<u8>(99, 100)? {
            defs.push(ModuleTypeDef::Export(
                "memory".into(),
                crate::core::EntityType::Memory(self.arbitrary_core_memory_type(u)?),
            ));
            exports.insert("memory".into());
            counts.memories += 1;
            has_memory = true;
        }

        // `canonical_abi_realloc`
        if counts.funcs < self.config.max_funcs
            && types.len() < self.config.max_types
            && u.ratio::<u8>(99, 100)?
        {
            let realloc_ty = Rc::new(crate::core::FuncType {
                params: vec![ValType::I32, ValType::I32, ValType::I32, ValType::I32],
                results: vec![ValType::I32],
            });
            let ty_idx = u32::try_from(types.len()).unwrap();
            types.push(realloc_ty.clone());
            defs.push(ModuleTypeDef::TypeDef(crate::core::CompositeType::Func(
                realloc_ty.clone(),
            )));
            defs.push(ModuleTypeDef::Export(
                "canonical_abi_realloc".into(),
                crate::core::EntityType::Func(ty_idx, realloc_ty),
            ));
            exports.insert("canonical_abi_realloc".into());
            counts.funcs += 1;
            has_canonical_abi_realloc = true;
        }

        // `canonical_abi_free`
        if counts.funcs < self.config.max_funcs
            && types.len() < self.config.max_types
            && u.ratio::<u8>(99, 100)?
        {
            let free_ty = Rc::new(crate::core::FuncType {
                params: vec![ValType::I32, ValType::I32, ValType::I32],
                results: vec![],
            });
            let ty_idx = u32::try_from(types.len()).unwrap();
            types.push(free_ty.clone());
            defs.push(ModuleTypeDef::TypeDef(crate::core::CompositeType::Func(
                free_ty.clone(),
            )));
            defs.push(ModuleTypeDef::Export(
                "canonical_abi_free".into(),
                crate::core::EntityType::Func(ty_idx, free_ty),
            ));
            exports.insert("canonical_abi_free".into());
            counts.funcs += 1;
            has_canonical_abi_free = true;
        }

        let mut entity_choices: Vec<
            fn(
                &ComponentBuilder,
                &mut Unstructured,
                &mut EntityCounts,
                &[Rc<crate::core::FuncType>],
            ) -> Result<crate::core::EntityType>,
        > = Vec::with_capacity(5);

        arbitrary_loop(u, 0, 100, |u| {
            *type_fuel = type_fuel.saturating_sub(1);
            if *type_fuel == 0 {
                return Ok(false);
            }

            let max_choice = if types.len() < self.config.max_types {
                // Check if the parent scope has core function types to alias
                if !types.is_empty()
                    || (!self.types.is_empty()
                        && !self.types.last().unwrap().core_func_types.is_empty())
                {
                    // Imports, exports, types, and aliases
                    3
                } else {
                    // Imports, exports, and types
                    2
                }
            } else {
                // Imports and exports
                1
            };

            match u.int_in_range::<u8>(0..=max_choice)? {
                // Import.
                0 => {
                    let module = crate::limited_string(100, u)?;
                    let existing_module_imports = imports.entry(module.clone()).or_default();
                    let field = crate::unique_string(100, existing_module_imports, u)?;
                    let entity_type = match self.arbitrary_core_entity_type(
                        u,
                        &types,
                        &mut entity_choices,
                        &mut counts,
                    )? {
                        None => return Ok(false),
                        Some(x) => x,
                    };
                    defs.push(ModuleTypeDef::Import(crate::core::Import {
                        module,
                        field,
                        entity_type,
                    }));
                }

                // Export.
                1 => {
                    let name = crate::unique_string(100, &mut exports, u)?;
                    let entity_ty = match self.arbitrary_core_entity_type(
                        u,
                        &types,
                        &mut entity_choices,
                        &mut counts,
                    )? {
                        None => return Ok(false),
                        Some(x) => x,
                    };
                    defs.push(ModuleTypeDef::Export(name, entity_ty));
                }

                // Type definition.
                2 => {
                    let ty = arbitrary_func_type(
                        u,
                        &self.config,
                        &self.core_valtypes,
                        if self.config.multi_value_enabled {
                            None
                        } else {
                            Some(1)
                        },
                        0,
                    )?;
                    types.push(ty.clone());
                    defs.push(ModuleTypeDef::TypeDef(crate::core::CompositeType::Func(ty)));
                }

                // Alias
                3 => {
                    let (count, index, kind) = self.arbitrary_outer_core_type_alias(u, &types)?;
                    let ty = match &kind {
                        CoreOuterAliasKind::Type(ty) => ty.clone(),
                    };
                    types.push(ty);
                    defs.push(ModuleTypeDef::OuterAlias {
                        count,
                        i: index,
                        kind,
                    });
                }

                _ => unreachable!(),
            }

            Ok(true)
        })?;

        Ok(Rc::new(ModuleType {
            defs,
            has_memory,
            has_canonical_abi_realloc,
            has_canonical_abi_free,
        }))
    }

    fn arbitrary_core_entity_type(
        &self,
        u: &mut Unstructured,
        types: &[Rc<crate::core::FuncType>],
        choices: &mut Vec<
            fn(
                &ComponentBuilder,
                &mut Unstructured,
                &mut EntityCounts,
                &[Rc<crate::core::FuncType>],
            ) -> Result<crate::core::EntityType>,
        >,
        counts: &mut EntityCounts,
    ) -> Result<Option<crate::core::EntityType>> {
        choices.clear();

        if counts.globals < self.config.max_globals {
            choices.push(|c, u, counts, _types| {
                counts.globals += 1;
                Ok(crate::core::EntityType::Global(
                    c.arbitrary_core_global_type(u)?,
                ))
            });
        }

        if counts.tables < self.config.max_tables {
            choices.push(|c, u, counts, _types| {
                counts.tables += 1;
                Ok(crate::core::EntityType::Table(
                    c.arbitrary_core_table_type(u)?,
                ))
            });
        }

        if counts.memories < self.config.max_memories {
            choices.push(|c, u, counts, _types| {
                counts.memories += 1;
                Ok(crate::core::EntityType::Memory(
                    c.arbitrary_core_memory_type(u)?,
                ))
            });
        }

        if types.iter().any(|ty| ty.results.is_empty())
            && self.config.exceptions_enabled
            && counts.tags < self.config.max_tags
        {
            choices.push(|c, u, counts, types| {
                counts.tags += 1;
                let tag_func_types = types
                    .iter()
                    .enumerate()
                    .filter(|(_, ty)| ty.results.is_empty())
                    .map(|(i, _)| u32::try_from(i).unwrap())
                    .collect::<Vec<_>>();
                Ok(crate::core::EntityType::Tag(
                    crate::core::arbitrary_tag_type(u, &tag_func_types, |idx| {
                        types[usize::try_from(idx).unwrap()].clone()
                    })?,
                ))
            });
        }

        if !types.is_empty() && counts.funcs < self.config.max_funcs {
            choices.push(|c, u, counts, types| {
                counts.funcs += 1;
                let ty_idx = u.int_in_range(0..=u32::try_from(types.len() - 1).unwrap())?;
                let ty = types[ty_idx as usize].clone();
                Ok(crate::core::EntityType::Func(ty_idx, ty))
            });
        }

        if choices.is_empty() {
            return Ok(None);
        }

        let f = u.choose(choices)?;
        let ty = f(self, u, counts, types)?;
        Ok(Some(ty))
    }

    fn arbitrary_core_valtype(&self, u: &mut Unstructured) -> Result<ValType> {
        Ok(*u.choose(&self.core_valtypes)?)
    }

    fn arbitrary_core_global_type(&self, u: &mut Unstructured) -> Result<crate::core::GlobalType> {
        Ok(crate::core::GlobalType {
            val_type: self.arbitrary_core_valtype(u)?,
            mutable: u.arbitrary()?,
            shared: false,
        })
    }

    fn arbitrary_core_table_type(&self, u: &mut Unstructured) -> Result<crate::core::TableType> {
        crate::core::arbitrary_table_type(u, &self.config, None)
    }

    fn arbitrary_core_memory_type(&self, u: &mut Unstructured) -> Result<crate::core::MemoryType> {
        crate::core::arbitrary_memtype(u, &self.config)
    }

    fn with_types_scope<T>(&mut self, f: impl FnOnce(&mut Self) -> Result<T>) -> Result<T> {
        self.types.push(Default::default());
        let result = f(self);
        self.types.pop();
        result
    }

    fn current_type_scope(&self) -> &TypesScope {
        self.types.last().unwrap()
    }

    fn current_type_scope_mut(&mut self) -> &mut TypesScope {
        self.types.last_mut().unwrap()
    }

    fn outer_types_scope(&self, count: u32) -> &TypesScope {
        &self.types[self.types.len() - 1 - usize::try_from(count).unwrap()]
    }

    fn outer_type(&self, count: u32, i: u32) -> &Rc<Type> {
        &self.outer_types_scope(count).types[usize::try_from(i).unwrap()]
    }

    fn arbitrary_component_type(
        &mut self,
        u: &mut Unstructured,
        type_fuel: &mut u32,
    ) -> Result<Rc<ComponentType>> {
        let mut defs = vec![];
        let mut imports = HashSet::new();
        let mut import_urls = HashSet::new();
        let mut exports = HashSet::new();
        let mut export_urls = HashSet::new();

        self.with_types_scope(|me| {
            arbitrary_loop(u, 0, 100, |u| {
                *type_fuel = type_fuel.saturating_sub(1);
                if *type_fuel == 0 {
                    return Ok(false);
                }

                if me.current_type_scope().can_ref_type() && u.int_in_range::<u8>(0..=3)? == 0 {
                    if let Some(ty) = me.arbitrary_type_ref(u, true, true)? {
                        // Imports.
                        let name = crate::unique_kebab_string(100, &mut imports, u)?;
                        let url = if u.arbitrary()? {
                            Some(crate::unique_url(100, &mut import_urls, u)?)
                        } else {
                            None
                        };
                        defs.push(ComponentTypeDef::Import(Import { name, url, ty }));
                        return Ok(true);
                    }

                    // Can't reference an arbitrary type, fallback to another definition.
                }

                // Type definitions, exports, and aliases.
                let def =
                    me.arbitrary_instance_type_def(u, &mut exports, &mut export_urls, type_fuel)?;
                defs.push(def.into());
                Ok(true)
            })
        })?;

        Ok(Rc::new(ComponentType { defs }))
    }

    fn arbitrary_instance_type(
        &mut self,
        u: &mut Unstructured,
        type_fuel: &mut u32,
    ) -> Result<Rc<InstanceType>> {
        let mut defs = vec![];
        let mut exports = HashSet::new();
        let mut export_urls = HashSet::new();

        self.with_types_scope(|me| {
            arbitrary_loop(u, 0, 100, |u| {
                *type_fuel = type_fuel.saturating_sub(1);
                if *type_fuel == 0 {
                    return Ok(false);
                }

                defs.push(me.arbitrary_instance_type_def(
                    u,
                    &mut exports,
                    &mut export_urls,
                    type_fuel,
                )?);
                Ok(true)
            })
        })?;

        Ok(Rc::new(InstanceType { defs }))
    }

    fn arbitrary_instance_type_def(
        &mut self,
        u: &mut Unstructured,
        exports: &mut HashSet<String>,
        export_urls: &mut HashSet<String>,
        type_fuel: &mut u32,
    ) -> Result<InstanceTypeDecl> {
        let mut choices: Vec<
            fn(
                &mut ComponentBuilder,
                &mut HashSet<String>,
                &mut HashSet<String>,
                &mut Unstructured,
                &mut u32,
            ) -> Result<InstanceTypeDecl>,
        > = Vec::with_capacity(3);

        // Export.
        if self.current_type_scope().can_ref_type() {
            choices.push(|me, exports, export_urls, u, _type_fuel| {
                let ty = me.arbitrary_type_ref(u, false, true)?.unwrap();
                if let ComponentTypeRef::Type(TypeBounds::Eq(idx)) = ty {
                    let ty = me.current_type_scope().get(idx).clone();
                    me.current_type_scope_mut().push(ty);
                }
                Ok(InstanceTypeDecl::Export {
                    name: crate::unique_kebab_string(100, exports, u)?,
                    url: if u.arbitrary()? {
                        Some(crate::unique_url(100, export_urls, u)?)
                    } else {
                        None
                    },
                    ty,
                })
            });
        }

        // Outer type alias.
        if self
            .types
            .iter()
            .any(|scope| !scope.types.is_empty() || !scope.core_types.is_empty())
        {
            choices.push(|me, _exports, _export_urls, u, _type_fuel| {
                let alias = me.arbitrary_outer_type_alias(u)?;
                match &alias {
                    Alias::Outer {
                        kind: OuterAliasKind::Type(ty),
                        ..
                    } => me.current_type_scope_mut().push(ty.clone()),
                    Alias::Outer {
                        kind: OuterAliasKind::CoreType(ty),
                        ..
                    } => me.current_type_scope_mut().push_core(ty.clone()),
                    _ => unreachable!(),
                };
                Ok(InstanceTypeDecl::Alias(alias))
            });
        }

        // Core type definition.
        choices.push(|me, _exports, _export_urls, u, type_fuel| {
            let ty = me.arbitrary_core_type(u, type_fuel)?;
            me.current_type_scope_mut().push_core(ty.clone());
            Ok(InstanceTypeDecl::CoreType(ty))
        });

        // Type definition.
        if self.types.len() < self.config.max_nesting_depth {
            choices.push(|me, _exports, _export_urls, u, type_fuel| {
                let ty = me.arbitrary_type(u, type_fuel)?;
                me.current_type_scope_mut().push(ty.clone());
                Ok(InstanceTypeDecl::Type(ty))
            });
        }

        let f = u.choose(&choices)?;
        f(self, exports, export_urls, u, type_fuel)
    }

    fn arbitrary_outer_core_type_alias(
        &self,
        u: &mut Unstructured,
        local_types: &[Rc<crate::core::FuncType>],
    ) -> Result<(u32, u32, CoreOuterAliasKind)> {
        let enclosing_type_len = if !self.types.is_empty() {
            self.types.last().unwrap().core_func_types.len()
        } else {
            0
        };

        assert!(!local_types.is_empty() || enclosing_type_len > 0);

        let max = enclosing_type_len + local_types.len() - 1;
        let i = u.int_in_range(0..=max)?;
        let (count, index, ty) = if i < enclosing_type_len {
            let enclosing = self.types.last().unwrap();
            let index = enclosing.core_func_types[i];
            (
                1,
                index,
                match enclosing.get_core(index).as_ref() {
                    CoreType::Func(ty) => ty.clone(),
                    CoreType::Module(_) => unreachable!(),
                },
            )
        } else if i - enclosing_type_len < local_types.len() {
            let i = i - enclosing_type_len;
            (0, u32::try_from(i).unwrap(), local_types[i].clone())
        } else {
            unreachable!()
        };

        Ok((count, index, CoreOuterAliasKind::Type(ty)))
    }

    fn arbitrary_outer_type_alias(&self, u: &mut Unstructured) -> Result<Alias> {
        let non_empty_types_scopes: Vec<_> = self
            .types
            .iter()
            .rev()
            .enumerate()
            .filter(|(_, scope)| !scope.types.is_empty() || !scope.core_types.is_empty())
            .collect();
        assert!(
            !non_empty_types_scopes.is_empty(),
            "precondition: there are non-empty types scopes"
        );

        let (count, scope) = u.choose(&non_empty_types_scopes)?;
        let count = u32::try_from(*count).unwrap();
        assert!(!scope.types.is_empty() || !scope.core_types.is_empty());

        let max_type_in_scope = scope.types.len() + scope.core_types.len() - 1;
        let i = u.int_in_range(0..=max_type_in_scope)?;

        let (i, kind) = if i < scope.types.len() {
            let i = u32::try_from(i).unwrap();
            (i, OuterAliasKind::Type(Rc::clone(scope.get(i))))
        } else if i - scope.types.len() < scope.core_types.len() {
            let i = u32::try_from(i - scope.types.len()).unwrap();
            (i, OuterAliasKind::CoreType(Rc::clone(scope.get_core(i))))
        } else {
            unreachable!()
        };

        Ok(Alias::Outer { count, i, kind })
    }

    fn arbitrary_func_type(
        &self,
        u: &mut Unstructured,
        type_fuel: &mut u32,
    ) -> Result<Rc<FuncType>> {
        let mut params = Vec::new();
        let mut results = Vec::new();
        let mut names = HashSet::new();

        // Note: parameters are currently limited to a maximum of 16
        // because any additional parameters will require indirect access
        // via a pointer argument; when this occurs, validation of any
        // lowered function will fail because it will be missing a
        // memory option (not yet implemented).
        //
        // When options are correctly specified on canonical functions,
        // we should increase this maximum to test indirect parameter
        // passing.
        arbitrary_loop(u, 0, 16, |u| {
            *type_fuel = type_fuel.saturating_sub(1);
            if *type_fuel == 0 {
                return Ok(false);
            }

            let name = crate::unique_kebab_string(100, &mut names, u)?;
            let ty = self.arbitrary_component_val_type(u)?;

            params.push((name, ty));

            Ok(true)
        })?;

        names.clear();

        // Likewise, the limit for results is 1 before the memory option is
        // required. When the memory option is implemented, this restriction
        // should be relaxed.
        arbitrary_loop(u, 0, 1, |u| {
            *type_fuel = type_fuel.saturating_sub(1);
            if *type_fuel == 0 {
                return Ok(false);
            }

            // If the result list is empty (i.e. first push), then arbitrarily give
            // the result a name. Otherwise, all of the subsequent items must be named.
            let name = if results.is_empty() {
                // Most of the time we should have a single, unnamed result.
                u.ratio::<u8>(10, 100)?
                    .then(|| crate::unique_kebab_string(100, &mut names, u))
                    .transpose()?
            } else {
                Some(crate::unique_kebab_string(100, &mut names, u)?)
            };

            let ty = self.arbitrary_component_val_type(u)?;

            results.push((name, ty));

            // There can be only one unnamed result.
            if results.len() == 1 && results[0].0.is_none() {
                return Ok(false);
            }

            Ok(true)
        })?;

        Ok(Rc::new(FuncType { params, results }))
    }

    fn arbitrary_component_val_type(&self, u: &mut Unstructured) -> Result<ComponentValType> {
        let max_choices = if self.current_type_scope().defined_types.is_empty() {
            0
        } else {
            1
        };
        match u.int_in_range(0..=max_choices)? {
            0 => Ok(ComponentValType::Primitive(
                self.arbitrary_primitive_val_type(u)?,
            )),
            1 => {
                let index = *u.choose(&self.current_type_scope().defined_types)?;
                let ty = Rc::clone(self.current_type_scope().get(index));
                Ok(ComponentValType::Type(index))
            }
            _ => unreachable!(),
        }
    }

    fn arbitrary_primitive_val_type(&self, u: &mut Unstructured) -> Result<PrimitiveValType> {
        match u.int_in_range(0..=12)? {
            0 => Ok(PrimitiveValType::Bool),
            1 => Ok(PrimitiveValType::S8),
            2 => Ok(PrimitiveValType::U8),
            3 => Ok(PrimitiveValType::S16),
            4 => Ok(PrimitiveValType::U16),
            5 => Ok(PrimitiveValType::S32),
            6 => Ok(PrimitiveValType::U32),
            7 => Ok(PrimitiveValType::S64),
            8 => Ok(PrimitiveValType::U64),
            9 => Ok(PrimitiveValType::F32),
            10 => Ok(PrimitiveValType::F64),
            11 => Ok(PrimitiveValType::Char),
            12 => Ok(PrimitiveValType::String),
            _ => unreachable!(),
        }
    }

    fn arbitrary_record_type(
        &self,
        u: &mut Unstructured,
        type_fuel: &mut u32,
    ) -> Result<RecordType> {
        let mut fields = vec![];
        let mut field_names = HashSet::new();
        arbitrary_loop(u, 0, 100, |u| {
            *type_fuel = type_fuel.saturating_sub(1);
            if *type_fuel == 0 {
                return Ok(false);
            }

            let name = crate::unique_kebab_string(100, &mut field_names, u)?;
            let ty = self.arbitrary_component_val_type(u)?;

            fields.push((name, ty));
            Ok(true)
        })?;
        Ok(RecordType { fields })
    }

    fn arbitrary_variant_type(
        &self,
        u: &mut Unstructured,
        type_fuel: &mut u32,
    ) -> Result<VariantType> {
        let mut cases = vec![];
        let mut case_names = HashSet::new();
        arbitrary_loop(u, 1, 100, |u| {
            *type_fuel = type_fuel.saturating_sub(1);
            if *type_fuel == 0 {
                return Ok(false);
            }

            let name = crate::unique_kebab_string(100, &mut case_names, u)?;

            let ty = u
                .arbitrary::<bool>()?
                .then(|| self.arbitrary_component_val_type(u))
                .transpose()?;

            let refines = if !cases.is_empty() && u.arbitrary()? {
                let max_cases = u32::try_from(cases.len() - 1).unwrap();
                Some(u.int_in_range(0..=max_cases)?)
            } else {
                None
            };

            cases.push((name, ty, refines));
            Ok(true)
        })?;

        Ok(VariantType { cases })
    }

    fn arbitrary_list_type(&self, u: &mut Unstructured) -> Result<ListType> {
        Ok(ListType {
            elem_ty: self.arbitrary_component_val_type(u)?,
        })
    }

    fn arbitrary_tuple_type(&self, u: &mut Unstructured, type_fuel: &mut u32) -> Result<TupleType> {
        let mut fields = vec![];
        arbitrary_loop(u, 0, 100, |u| {
            *type_fuel = type_fuel.saturating_sub(1);
            if *type_fuel == 0 {
                return Ok(false);
            }

            fields.push(self.arbitrary_component_val_type(u)?);
            Ok(true)
        })?;
        Ok(TupleType { fields })
    }

    fn arbitrary_flags_type(&self, u: &mut Unstructured, type_fuel: &mut u32) -> Result<FlagsType> {
        let mut fields = vec![];
        let mut field_names = HashSet::new();
        arbitrary_loop(u, 0, 100, |u| {
            *type_fuel = type_fuel.saturating_sub(1);
            if *type_fuel == 0 {
                return Ok(false);
            }

            fields.push(crate::unique_kebab_string(100, &mut field_names, u)?);
            Ok(true)
        })?;
        Ok(FlagsType { fields })
    }

    fn arbitrary_enum_type(&self, u: &mut Unstructured, type_fuel: &mut u32) -> Result<EnumType> {
        let mut variants = vec![];
        let mut variant_names = HashSet::new();
        arbitrary_loop(u, 1, 100, |u| {
            *type_fuel = type_fuel.saturating_sub(1);
            if *type_fuel == 0 {
                return Ok(false);
            }

            variants.push(crate::unique_kebab_string(100, &mut variant_names, u)?);
            Ok(true)
        })?;
        Ok(EnumType { variants })
    }

    fn arbitrary_option_type(&self, u: &mut Unstructured) -> Result<OptionType> {
        Ok(OptionType {
            inner_ty: self.arbitrary_component_val_type(u)?,
        })
    }

    fn arbitrary_result_type(&self, u: &mut Unstructured) -> Result<ResultType> {
        Ok(ResultType {
            ok_ty: u
                .arbitrary::<bool>()?
                .then(|| self.arbitrary_component_val_type(u))
                .transpose()?,
            err_ty: u
                .arbitrary::<bool>()?
                .then(|| self.arbitrary_component_val_type(u))
                .transpose()?,
        })
    }

    fn arbitrary_defined_type(
        &self,
        u: &mut Unstructured,
        type_fuel: &mut u32,
    ) -> Result<DefinedType> {
        match u.int_in_range(0..=8)? {
            0 => Ok(DefinedType::Primitive(
                self.arbitrary_primitive_val_type(u)?,
            )),
            1 => Ok(DefinedType::Record(
                self.arbitrary_record_type(u, type_fuel)?,
            )),
            2 => Ok(DefinedType::Variant(
                self.arbitrary_variant_type(u, type_fuel)?,
            )),
            3 => Ok(DefinedType::List(self.arbitrary_list_type(u)?)),
            4 => Ok(DefinedType::Tuple(self.arbitrary_tuple_type(u, type_fuel)?)),
            5 => Ok(DefinedType::Flags(self.arbitrary_flags_type(u, type_fuel)?)),
            6 => Ok(DefinedType::Enum(self.arbitrary_enum_type(u, type_fuel)?)),
            7 => Ok(DefinedType::Option(self.arbitrary_option_type(u)?)),
            8 => Ok(DefinedType::Result(self.arbitrary_result_type(u)?)),
            _ => unreachable!(),
        }
    }

    fn push_import(&mut self, name: String, url: Option<String>, ty: ComponentTypeRef) {
        let nth = match self.ensure_section(
            |sec| matches!(sec, Section::Import(_)),
            || Section::Import(ImportSection { imports: vec![] }),
        ) {
            Section::Import(sec) => {
                sec.imports.push(Import { name, url, ty });
                sec.imports.len() - 1
            }
            _ => unreachable!(),
        };
        let section_index = self.component().component.sections.len() - 1;

        match ty {
            ComponentTypeRef::Module(_) => {
                self.total_modules += 1;
                self.component_mut().modules.push((section_index, nth));
            }
            ComponentTypeRef::Func(ty_index) => {
                let func_ty = match self.current_type_scope().get(ty_index).as_ref() {
                    Type::Func(ty) => ty.clone(),
                    _ => unreachable!(),
                };

                if func_ty.is_scalar() {
                    let func_index = u32::try_from(self.component().component_funcs.len()).unwrap();
                    self.component_mut().scalar_component_funcs.push(func_index);
                }

                let func_index = u32::try_from(self.component().funcs.len()).unwrap();
                self.component_mut()
                    .funcs
                    .push(ComponentOrCoreFuncType::Component(func_ty));

                self.component_mut().component_funcs.push(func_index);
            }
            ComponentTypeRef::Value(ty) => {
                self.total_values += 1;
                self.component_mut().values.push(ty);
            }
            ComponentTypeRef::Type(TypeBounds::Eq(ty_index)) => {
                let ty = self.current_type_scope().get(ty_index).clone();
                self.current_type_scope_mut().push(ty);
            }
            ComponentTypeRef::Type(TypeBounds::SubResource) => {
                unimplemented!()
            }
            ComponentTypeRef::Instance(ty_index) => {
                let instance_ty = match self.current_type_scope().get(ty_index).as_ref() {
                    Type::Instance(ty) => ty.clone(),
                    _ => unreachable!(),
                };

                self.total_instances += 1;
                self.component_mut()
                    .instances
                    .push(ComponentOrCoreInstanceType::Component(instance_ty));
            }
            ComponentTypeRef::Component(_) => {
                self.total_components += 1;
                self.component_mut().components.push((section_index, nth));
            }
        }
    }

    fn core_function_type(&self, core_func_index: u32) -> &Rc<crate::core::FuncType> {
        self.component().funcs[self.component().core_funcs[core_func_index as usize] as usize]
            .as_core()
    }

    fn component_function_type(&self, func_index: u32) -> &Rc<FuncType> {
        self.component().funcs[self.component().component_funcs[func_index as usize] as usize]
            .as_component()
    }

    fn push_func(&mut self, func: Func) {
        let nth = match self.component_mut().component.sections.last_mut() {
            Some(Section::Canonical(CanonicalSection { funcs })) => funcs.len(),
            _ => {
                self.push_section(Section::Canonical(CanonicalSection { funcs: vec![] }));
                0
            }
        };
        let section_index = self.component().component.sections.len() - 1;

        let func_index = u32::try_from(self.component().funcs.len()).unwrap();

        let ty = match &func {
            Func::CanonLift { func_ty, .. } => {
                let ty = Rc::clone(self.current_type_scope().get_func(*func_ty));
                if ty.is_scalar() {
                    let func_index = u32::try_from(self.component().component_funcs.len()).unwrap();
                    self.component_mut().scalar_component_funcs.push(func_index);
                }
                self.component_mut().component_funcs.push(func_index);
                ComponentOrCoreFuncType::Component(ty)
            }
            Func::CanonLower {
                func_index: comp_func_index,
                ..
            } => {
                let comp_func_ty = self.component_function_type(*comp_func_index);
                let core_func_ty = canonical_abi_for(comp_func_ty);
                self.component_mut().core_funcs.push(func_index);
                ComponentOrCoreFuncType::Core(core_func_ty)
            }
        };

        self.component_mut().funcs.push(ty);

        match self.component_mut().component.sections.last_mut() {
            Some(Section::Canonical(CanonicalSection { funcs })) => funcs.push(func),
            _ => unreachable!(),
        }
    }

    fn arbitrary_import_section(&mut self, u: &mut Unstructured) -> Result<Step> {
        self.push_section(Section::Import(ImportSection { imports: vec![] }));

        let min = if self.fill_minimums {
            self.config
                .min_imports
                .saturating_sub(self.component().num_imports)
        } else {
            // Allow generating empty sections. We can always fill in the required
            // minimum later.
            0
        };
        let max = self.config.max_imports - self.component().num_imports;

        crate::arbitrary_loop(u, min, max, |u| {
            match self.arbitrary_type_ref(u, true, false)? {
                Some(ty) => {
                    let name =
                        crate::unique_kebab_string(100, &mut self.component_mut().import_names, u)?;
                    let url = if u.arbitrary()? {
                        Some(crate::unique_url(
                            100,
                            &mut self.component_mut().import_urls,
                            u,
                        )?)
                    } else {
                        None
                    };
                    self.push_import(name, url, ty);
                    Ok(true)
                }
                None => Ok(false),
            }
        })?;

        Ok(Step::StillBuilding)
    }

    fn arbitrary_canonical_section(&mut self, u: &mut Unstructured) -> Result<Step> {
        self.push_section(Section::Canonical(CanonicalSection { funcs: vec![] }));

        let min = if self.fill_minimums {
            self.config
                .min_funcs
                .saturating_sub(self.component().funcs.len())
        } else {
            // Allow generating empty sections. We can always fill in the
            // required minimum later.
            0
        };
        let max = self.config.max_funcs - self.component().funcs.len();

        let mut choices: Vec<fn(&mut Unstructured, &mut ComponentBuilder) -> Result<Option<Func>>> =
            Vec::with_capacity(2);

        crate::arbitrary_loop(u, min, max, |u| {
            choices.clear();

            // NB: We only lift/lower scalar component functions.
            //
            // If we generated lifting and lowering of compound value types,
            // the probability of generating a corresponding Wasm module that
            // generates valid instances of the compound value types would
            // be vanishingly tiny (e.g. for `list<string>` we would have to
            // generate a core Wasm module that correctly produces a pointer and
            // length for a memory region that itself is a series of pointers
            // and lengths of valid strings, as well as `canonical_abi_realloc`
            // and `canonical_abi_free` functions that do the right thing).
            //
            // This is a pretty serious limitation of `wasm-smith`'s component
            // types support, but it is one we are intentionally
            // accepting. `wasm-smith` will focus on generating arbitrary
            // component sections, structures, and import/export topologies; not
            // component functions and core Wasm implementations of component
            // functions. In the future, we intend to build a new, distinct test
            // case generator specifically for exercising component functions
            // and the canonical ABI. This new generator won't emit arbitrary
            // component sections, structures, or import/export topologies, and
            // will instead leave that to `wasm-smith`.

            if !self.component().scalar_component_funcs.is_empty() {
                choices.push(|u, c| {
                    let func_index = *u.choose(&c.component().scalar_component_funcs)?;
                    Ok(Some(Func::CanonLower {
                        // Scalar component functions don't use any canonical options.
                        options: vec![],
                        func_index,
                    }))
                });
            }

            if !self.component().core_funcs.is_empty() {
                choices.push(|u, c| {
                    let core_func_index = u.int_in_range(
                        0..=u32::try_from(c.component().core_funcs.len() - 1).unwrap(),
                    )?;
                    let core_func_ty = c.core_function_type(core_func_index);
                    let comp_func_ty = inverse_scalar_canonical_abi_for(u, core_func_ty)?;

                    let func_ty = if let Some(indices) = c
                        .current_type_scope()
                        .func_type_to_indices
                        .get(&comp_func_ty)
                    {
                        // If we've already defined this component function type
                        // one or more times, then choose one of those
                        // definitions arbitrarily.
                        debug_assert!(!indices.is_empty());
                        *u.choose(indices)?
                    } else if c.current_type_scope().types.len() < c.config.max_types {
                        // If we haven't already defined this component function
                        // type, and we haven't defined the configured maximum
                        // amount of types yet, then just define this type.
                        let ty = Rc::new(Type::Func(Rc::new(comp_func_ty)));
                        c.push_type(ty)
                    } else {
                        // Otherwise, give up on lifting this function.
                        return Ok(None);
                    };

                    Ok(Some(Func::CanonLift {
                        func_ty,
                        // Scalar functions don't use any canonical options.
                        options: vec![],
                        core_func_index,
                    }))
                });
            }

            if choices.is_empty() {
                return Ok(false);
            }

            let f = u.choose(&choices)?;
            if let Some(func) = f(u, self)? {
                self.push_func(func);
            }

            Ok(true)
        })?;

        Ok(Step::StillBuilding)
    }

    fn arbitrary_core_module_section(&mut self, u: &mut Unstructured) -> Result<Step> {
        let module = crate::core::Module::new_internal(
            self.config.clone(),
            u,
            crate::core::DuplicateImportsBehavior::Disallowed,
        )?;
        self.push_section(Section::CoreModule(module));
        self.total_modules += 1;
        Ok(Step::StillBuilding)
    }

    fn arbitrary_component_section(&mut self, u: &mut Unstructured) -> Result<Step> {
        self.types.push(TypesScope::default());
        self.components.push(ComponentContext::empty());
        self.total_components += 1;
        Ok(Step::StillBuilding)
    }

    fn arbitrary_instance_section(&mut self, u: &mut Unstructured) -> Result<()> {
        todo!()
    }

    fn arbitrary_export_section(&mut self, u: &mut Unstructured) -> Result<()> {
        todo!()
    }

    fn arbitrary_start_section(&mut self, u: &mut Unstructured) -> Result<()> {
        todo!()
    }

    fn arbitrary_alias_section(&mut self, u: &mut Unstructured) -> Result<()> {
        todo!()
    }
}

fn canonical_abi_for(func_ty: &FuncType) -> Rc<crate::core::FuncType> {
    let to_core_ty = |ty| match ty {
        ComponentValType::Primitive(prim_ty) => match prim_ty {
            PrimitiveValType::Char
            | PrimitiveValType::Bool
            | PrimitiveValType::S8
            | PrimitiveValType::U8
            | PrimitiveValType::S16
            | PrimitiveValType::U16
            | PrimitiveValType::S32
            | PrimitiveValType::U32 => ValType::I32,
            PrimitiveValType::S64 | PrimitiveValType::U64 => ValType::I64,
            PrimitiveValType::F32 => ValType::F32,
            PrimitiveValType::F64 => ValType::F64,
            PrimitiveValType::String => {
                unimplemented!("non-scalar types are not supported yet")
            }
        },
        ComponentValType::Type(_) => unimplemented!("non-scalar types are not supported yet"),
    };

    Rc::new(crate::core::FuncType {
        params: func_ty
            .params
            .iter()
            .map(|(_, ty)| to_core_ty(*ty))
            .collect(),
        results: func_ty
            .results
            .iter()
            .map(|(_, ty)| to_core_ty(*ty))
            .collect(),
    })
}

fn inverse_scalar_canonical_abi_for(
    u: &mut Unstructured,
    core_func_ty: &crate::core::FuncType,
) -> Result<FuncType> {
    let from_core_ty = |u: &mut Unstructured, core_ty| match core_ty {
        ValType::I32 => u
            .choose(&[
                ComponentValType::Primitive(PrimitiveValType::Char),
                ComponentValType::Primitive(PrimitiveValType::Bool),
                ComponentValType::Primitive(PrimitiveValType::S8),
                ComponentValType::Primitive(PrimitiveValType::U8),
                ComponentValType::Primitive(PrimitiveValType::S16),
                ComponentValType::Primitive(PrimitiveValType::U16),
                ComponentValType::Primitive(PrimitiveValType::S32),
                ComponentValType::Primitive(PrimitiveValType::U32),
            ])
            .cloned(),
        ValType::I64 => u
            .choose(&[
                ComponentValType::Primitive(PrimitiveValType::S64),
                ComponentValType::Primitive(PrimitiveValType::U64),
            ])
            .cloned(),
        ValType::F32 => Ok(ComponentValType::Primitive(PrimitiveValType::F32)),
        ValType::F64 => Ok(ComponentValType::Primitive(PrimitiveValType::F64)),
        ValType::V128 | ValType::Ref(_) => {
            unreachable!("not used in canonical ABI")
        }
    };

    let mut names = HashSet::default();
    let mut params = vec![];

    for core_ty in &core_func_ty.params {
        params.push((
            crate::unique_kebab_string(100, &mut names, u)?,
            from_core_ty(u, *core_ty)?,
        ));
    }

    names.clear();

    let results = match core_func_ty.results.len() {
        0 => Vec::new(),
        1 => vec![(
            if u.arbitrary()? {
                Some(crate::unique_kebab_string(100, &mut names, u)?)
            } else {
                None
            },
            from_core_ty(u, core_func_ty.results[0])?,
        )],
        _ => unimplemented!("non-scalar types are not supported yet"),
    };

    Ok(FuncType { params, results })
}

#[derive(Debug)]
enum Section {
    Custom(CustomSection),
    CoreModule(crate::Module),
    CoreInstance(CoreInstanceSection),
    CoreType(CoreTypeSection),
    Component(Component),
    Instance(InstanceSection),
    Alias(AliasSection),
    Type(TypeSection),
    Canonical(CanonicalSection),
    Start(StartSection),
    Import(ImportSection),
    Export(ExportSection),
}

#[derive(Debug)]
struct CustomSection {
    name: String,
    data: Vec<u8>,
}

impl<'a> Arbitrary<'a> for CustomSection {
    fn arbitrary(u: &mut Unstructured<'a>) -> Result<Self> {
        let name = crate::limited_string(1_000, u)?;
        let data = u.arbitrary()?;
        Ok(CustomSection { name, data })
    }
}

#[derive(Debug)]
struct TypeSection {
    types: Vec<Rc<Type>>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum CoreType {
    Func(Rc<crate::core::FuncType>),
    Module(Rc<ModuleType>),
}

#[derive(Clone, Debug, PartialEq, Eq, Hash, Default)]
struct ModuleType {
    defs: Vec<ModuleTypeDef>,
    has_memory: bool,
    has_canonical_abi_realloc: bool,
    has_canonical_abi_free: bool,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum ModuleTypeDef {
    TypeDef(crate::core::CompositeType),
    Import(crate::core::Import),
    OuterAlias {
        count: u32,
        i: u32,
        kind: CoreOuterAliasKind,
    },
    Export(String, crate::core::EntityType),
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum Type {
    Defined(DefinedType),
    Func(Rc<FuncType>),
    Component(Rc<ComponentType>),
    Instance(Rc<InstanceType>),
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum CoreInstanceExportAliasKind {
    Func,
    Table,
    Memory,
    Global,
    Tag,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum CoreOuterAliasKind {
    Type(Rc<crate::core::FuncType>),
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum Alias {
    InstanceExport {
        instance: u32,
        name: String,
        kind: InstanceExportAliasKind,
    },
    CoreInstanceExport {
        instance: u32,
        name: String,
        kind: CoreInstanceExportAliasKind,
    },
    Outer {
        count: u32,
        i: u32,
        kind: OuterAliasKind,
    },
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum InstanceExportAliasKind {
    Module,
    Component,
    Instance,
    Func,
    Value,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum OuterAliasKind {
    Module,
    Component,
    CoreType(Rc<CoreType>),
    Type(Rc<Type>),
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct ComponentType {
    defs: Vec<ComponentTypeDef>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum ComponentTypeDef {
    CoreType(Rc<CoreType>),
    Type(Rc<Type>),
    Alias(Alias),
    Import(Import),
    Export {
        name: String,
        url: Option<String>,
        ty: ComponentTypeRef,
    },
}

impl From<InstanceTypeDecl> for ComponentTypeDef {
    fn from(def: InstanceTypeDecl) -> Self {
        match def {
            InstanceTypeDecl::CoreType(t) => Self::CoreType(t),
            InstanceTypeDecl::Type(t) => Self::Type(t),
            InstanceTypeDecl::Export { name, url, ty } => Self::Export { name, url, ty },
            InstanceTypeDecl::Alias(a) => Self::Alias(a),
        }
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct InstanceType {
    defs: Vec<InstanceTypeDecl>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum InstanceTypeDecl {
    CoreType(Rc<CoreType>),
    Type(Rc<Type>),
    Alias(Alias),
    Export {
        name: String,
        url: Option<String>,
        ty: ComponentTypeRef,
    },
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct FuncType {
    params: Vec<(String, ComponentValType)>,
    results: Vec<(Option<String>, ComponentValType)>,
}

impl FuncType {
    fn unnamed_result_ty(&self) -> Option<ComponentValType> {
        if self.results.len() == 1 {
            let (name, ty) = &self.results[0];
            if name.is_none() {
                return Some(*ty);
            }
        }
        None
    }

    fn is_scalar(&self) -> bool {
        self.params.iter().all(|(_, ty)| is_scalar(ty))
            && self.results.len() == 1
            && is_scalar(&self.results[0].1)
    }
}

fn is_scalar(ty: &ComponentValType) -> bool {
    match ty {
        ComponentValType::Primitive(prim) => match prim {
            PrimitiveValType::Bool
            | PrimitiveValType::S8
            | PrimitiveValType::U8
            | PrimitiveValType::S16
            | PrimitiveValType::U16
            | PrimitiveValType::S32
            | PrimitiveValType::U32
            | PrimitiveValType::S64
            | PrimitiveValType::U64
            | PrimitiveValType::F32
            | PrimitiveValType::F64
            | PrimitiveValType::Char => true,
            PrimitiveValType::String => false,
        },
        ComponentValType::Type(_) => false,
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
enum DefinedType {
    Primitive(PrimitiveValType),
    Record(RecordType),
    Variant(VariantType),
    List(ListType),
    Tuple(TupleType),
    Flags(FlagsType),
    Enum(EnumType),
    Option(OptionType),
    Result(ResultType),
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct RecordType {
    fields: Vec<(String, ComponentValType)>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct VariantType {
    cases: Vec<(String, Option<ComponentValType>, Option<u32>)>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct ListType {
    elem_ty: ComponentValType,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct TupleType {
    fields: Vec<ComponentValType>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct FlagsType {
    fields: Vec<String>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct EnumType {
    variants: Vec<String>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct OptionType {
    inner_ty: ComponentValType,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct ResultType {
    ok_ty: Option<ComponentValType>,
    err_ty: Option<ComponentValType>,
}

#[derive(Debug)]
struct ImportSection {
    imports: Vec<Import>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct Import {
    name: String,
    url: Option<String>,
    ty: ComponentTypeRef,
}

#[derive(Debug)]
struct CanonicalSection {
    funcs: Vec<Func>,
}

#[derive(Debug)]
enum Func {
    CanonLift {
        func_ty: u32,
        options: Vec<CanonOpt>,
        core_func_index: u32,
    },
    CanonLower {
        options: Vec<CanonOpt>,
        func_index: u32,
    },
}

#[derive(Debug)]
enum CanonOpt {
    StringUtf8,
    StringUtf16,
    StringLatin1Utf16,
    Memory(u32),
    Realloc(u32),
    PostReturn(u32),
}

#[derive(Debug)]
struct InstanceSection {}

#[derive(Debug)]
struct ExportSection {}

#[derive(Debug)]
struct StartSection {}

#[derive(Debug)]
struct AliasSection {}

#[derive(Debug)]
struct CoreInstanceSection {}

#[derive(Debug)]
struct CoreTypeSection {
    types: Vec<Rc<CoreType>>,
}

fn arbitrary_func_type(
    u: &mut Unstructured,
    config: &Config,
    valtypes: &[ValType],
    max_results: Option<usize>,
    type_ref_limit: u32,
) -> Result<Rc<crate::core::FuncType>> {
    let mut params = vec![];
    let mut results = vec![];
    arbitrary_loop(u, 0, 20, |u| {
        params.push(arbitrary_valtype(u, config, valtypes, type_ref_limit)?);
        Ok(true)
    })?;
    arbitrary_loop(u, 0, max_results.unwrap_or(20), |u| {
        results.push(arbitrary_valtype(u, config, valtypes, type_ref_limit)?);
        Ok(true)
    })?;
    Ok(Rc::new(crate::core::FuncType { params, results }))
}

fn arbitrary_valtype(
    u: &mut Unstructured,
    config: &Config,
    valtypes: &[ValType],
    type_ref_limit: u32,
) -> Result<ValType> {
    if config.gc_enabled && type_ref_limit > 0 && u.ratio(1, 20)? {
        Ok(ValType::Ref(RefType {
            // TODO: For now, only create allow nullable reference
            // types. Eventually we should support non-nullable reference types,
            // but this means that we will also need to recognize when it is
            // impossible to create an instance of the reference (eg `(ref
            // nofunc)` has no instances, and self-referential types that
            // contain a non-null self-reference are also impossible to create).
            nullable: true,
            heap_type: HeapType::Concrete(u.int_in_range(0..=type_ref_limit - 1)?),
        }))
    } else {
        Ok(*u.choose(valtypes)?)
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-smith-0.210.0/src/component/encode.rs

Source (jump to first uncovered line)
use std::borrow::Cow;

use super::*;
use wasm_encoder::{ComponentExportKind, ComponentOuterAliasKind, ExportKind};

impl Component {
    /// Encode this Wasm component into bytes.
    pub fn to_bytes(&self) -> Vec<u8> {
        self.encoded().finish()
    }

    fn encoded(&self) -> wasm_encoder::Component {
        let mut component = wasm_encoder::Component::new();
        for section in &self.sections {
            section.encode(&mut component);
        }
        component
    }
}

impl Section {
    fn encode(&self, component: &mut wasm_encoder::Component) {
        match self {
            Self::Custom(sec) => sec.encode(component),
            Self::CoreModule(module) => {
                let bytes = module.to_bytes();
                component.section(&wasm_encoder::RawSection {
                    id: wasm_encoder::ComponentSectionId::CoreModule as u8,
                    data: &bytes,
                });
            }
            Self::CoreInstance(_) => todo!(),
            Self::CoreType(sec) => sec.encode(component),
            Self::Component(comp) => {
                let bytes = comp.to_bytes();
                component.section(&wasm_encoder::RawSection {
                    id: wasm_encoder::ComponentSectionId::Component as u8,
                    data: &bytes,
                });
            }
            Self::Instance(_) => todo!(),
            Self::Alias(_) => todo!(),
            Self::Type(sec) => sec.encode(component),
            Self::Canonical(sec) => sec.encode(component),
            Self::Start(_) => todo!(),
            Self::Import(sec) => sec.encode(component),
            Self::Export(_) => todo!(),
        }
    }
}

impl CustomSection {
    fn encode(&self, component: &mut wasm_encoder::Component) {
        component.section(&wasm_encoder::CustomSection {
            name: (&self.name).into(),
            data: Cow::Borrowed(&self.data),
        });
    }
}

impl TypeSection {
    fn encode(&self, component: &mut wasm_encoder::Component) {
        let mut sec = wasm_encoder::ComponentTypeSection::new();
        for ty in &self.types {
            ty.encode(sec.ty());
        }
        component.section(&sec);
    }
}

impl ImportSection {
    fn encode(&self, component: &mut wasm_encoder::Component) {
        let mut sec = wasm_encoder::ComponentImportSection::new();
        for imp in &self.imports {
            sec.import(&imp.name, imp.ty);
        }
        component.section(&sec);
    }
}

impl CanonicalSection {
    fn encode(&self, component: &mut wasm_encoder::Component) {
        let mut sec = wasm_encoder::CanonicalFunctionSection::new();
        for func in &self.funcs {
            match func {
                Func::CanonLift {
                    func_ty,
                    options,
                    core_func_index,
                } => {
                    let options = translate_canon_opt(options);
                    sec.lift(*core_func_index, *func_ty, options);
                }
                Func::CanonLower {
                    options,
                    func_index,
                } => {
                    let options = translate_canon_opt(options);
                    sec.lower(*func_index, options);
                }
            }
        }
        component.section(&sec);
    }
}

impl CoreTypeSection {
    fn encode(&self, component: &mut wasm_encoder::Component) {
        let mut sec = wasm_encoder::CoreTypeSection::new();
        for ty in &self.types {
            ty.encode(sec.ty());
        }
        component.section(&sec);
    }
}

impl CoreType {
    fn encode(&self, enc: wasm_encoder::CoreTypeEncoder<'_>) {
        match self {
            Self::Func(ty) => {
                enc.function(ty.params.iter().copied(), ty.results.iter().copied());
            }
            Self::Module(mod_ty) => {
                let mut enc_mod_ty = wasm_encoder::ModuleType::new();
                for def in &mod_ty.defs {
                    match def {
                        ModuleTypeDef::TypeDef(crate::core::CompositeType::Func(func_ty)) => {
                            enc_mod_ty.ty().function(
                                func_ty.params.iter().copied(),
                                func_ty.results.iter().copied(),
                            );
                        }
                        ModuleTypeDef::TypeDef(_) => {
                            unimplemented!("non-func types in a component's module type")
                        }
                        ModuleTypeDef::OuterAlias { count, i, kind } => match kind {
                            CoreOuterAliasKind::Type(_) => {
                                enc_mod_ty.alias_outer_core_type(*count, *i);
                            }
                        },
                        ModuleTypeDef::Import(imp) => {
                            enc_mod_ty.import(
                                &imp.module,
                                &imp.field,
                                crate::core::encode::translate_entity_type(&imp.entity_type),
                            );
                        }
                        ModuleTypeDef::Export(name, ty) => {
                            enc_mod_ty.export(name, crate::core::encode::translate_entity_type(ty));
                        }
                    }
                }
                enc.module(&enc_mod_ty);
            }
        }
    }
}

impl Type {
    fn encode(&self, enc: wasm_encoder::ComponentTypeEncoder<'_>) {
        match self {
            Self::Defined(ty) => {
                ty.encode(enc.defined_type());
            }
            Self::Func(func_ty) => {
                let mut f = enc.function();

                f.params(func_ty.params.iter().map(|(name, ty)| (name.as_str(), *ty)));

                if let Some(ty) = func_ty.unnamed_result_ty() {
                    f.result(ty);
                } else {
                    f.results(
                        func_ty
                            .results
                            .iter()
                            .map(|(name, ty)| (name.as_deref().unwrap(), *ty)),
                    );
                }
            }
            Self::Component(comp_ty) => {
                let mut enc_comp_ty = wasm_encoder::ComponentType::new();
                for def in &comp_ty.defs {
                    match def {
                        ComponentTypeDef::Import(imp) => {
                            enc_comp_ty.import(&imp.name, imp.ty);
                        }
                        ComponentTypeDef::CoreType(ty) => {
                            ty.encode(enc_comp_ty.core_type());
                        }
                        ComponentTypeDef::Type(ty) => {
                            ty.encode(enc_comp_ty.ty());
                        }
                        ComponentTypeDef::Export { name, url: _, ty } => {
                            enc_comp_ty.export(name, *ty);
                        }
                        ComponentTypeDef::Alias(a) => {
                            enc_comp_ty.alias(translate_alias(a));
                        }
                    }
                }
                enc.component(&enc_comp_ty);
            }
            Self::Instance(inst_ty) => {
                let mut enc_inst_ty = wasm_encoder::InstanceType::new();
                for def in &inst_ty.defs {
                    match def {
                        InstanceTypeDecl::CoreType(ty) => {
                            ty.encode(enc_inst_ty.core_type());
                        }
                        InstanceTypeDecl::Type(ty) => {
                            ty.encode(enc_inst_ty.ty());
                        }
                        InstanceTypeDecl::Export { name, url: _, ty } => {
                            enc_inst_ty.export(name, *ty);
                        }
                        InstanceTypeDecl::Alias(a) => {
                            enc_inst_ty.alias(translate_alias(a));
                        }
                    }
                }
                enc.instance(&enc_inst_ty);
            }
        }
    }
}

impl DefinedType {
    fn encode(&self, enc: wasm_encoder::ComponentDefinedTypeEncoder<'_>) {
        match self {
            Self::Primitive(ty) => enc.primitive(*ty),
            Self::Record(ty) => {
                enc.record(ty.fields.iter().map(|(name, ty)| (name.as_str(), *ty)));
            }
            Self::Variant(ty) => {
                enc.variant(
                    ty.cases
                        .iter()
                        .map(|(name, ty, refines)| (name.as_str(), *ty, *refines)),
                );
            }
            Self::List(ty) => {
                enc.list(ty.elem_ty);
            }
            Self::Tuple(ty) => {
                enc.tuple(ty.fields.iter().copied());
            }
            Self::Flags(ty) => {
                enc.flags(ty.fields.iter().map(|f| f.as_str()));
            }
            Self::Enum(ty) => {
                enc.enum_type(ty.variants.iter().map(|v| v.as_str()));
            }
            Self::Option(ty) => {
                enc.option(ty.inner_ty);
            }
            Self::Result(ty) => {
                enc.result(ty.ok_ty, ty.err_ty);
            }
        }
    }
}

fn translate_canon_opt(options: &[CanonOpt]) -> Vec<wasm_encoder::CanonicalOption> {
    options
        .iter()
        .map(|o| match o {
            CanonOpt::StringUtf8 => wasm_encoder::CanonicalOption::UTF8,
            CanonOpt::StringUtf16 => wasm_encoder::CanonicalOption::UTF16,
            CanonOpt::StringLatin1Utf16 => wasm_encoder::CanonicalOption::CompactUTF16,
            CanonOpt::Memory(idx) => wasm_encoder::CanonicalOption::Memory(*idx),
            CanonOpt::Realloc(idx) => wasm_encoder::CanonicalOption::Realloc(*idx),
            CanonOpt::PostReturn(idx) => wasm_encoder::CanonicalOption::PostReturn(*idx),
        })
        .collect()
}

fn translate_alias(alias: &Alias) -> wasm_encoder::Alias<'_> {
    match alias {
        Alias::InstanceExport {
            instance,
            name,
            kind,
        } => wasm_encoder::Alias::InstanceExport {
            instance: *instance,
            name,
            kind: match kind {
                InstanceExportAliasKind::Module => ComponentExportKind::Module,
                InstanceExportAliasKind::Component => ComponentExportKind::Component,
                InstanceExportAliasKind::Instance => ComponentExportKind::Instance,
                InstanceExportAliasKind::Func => ComponentExportKind::Func,
                InstanceExportAliasKind::Value => ComponentExportKind::Value,
            },
        },
        Alias::CoreInstanceExport {
            instance,
            name,
            kind,
        } => wasm_encoder::Alias::CoreInstanceExport {
            instance: *instance,
            name,
            kind: match kind {
                CoreInstanceExportAliasKind::Func => ExportKind::Func,
                CoreInstanceExportAliasKind::Table => ExportKind::Table,
                CoreInstanceExportAliasKind::Global => ExportKind::Global,
                CoreInstanceExportAliasKind::Memory => ExportKind::Memory,
                CoreInstanceExportAliasKind::Tag => ExportKind::Tag,
            },
        },
        Alias::Outer { count, i, kind } => wasm_encoder::Alias::Outer {
            count: *count,
            index: *i,
            kind: match kind {
                OuterAliasKind::Module => ComponentOuterAliasKind::CoreModule,
                OuterAliasKind::Component => ComponentOuterAliasKind::Component,
                OuterAliasKind::Type(_) => ComponentOuterAliasKind::Type,
                OuterAliasKind::CoreType(_) => ComponentOuterAliasKind::CoreType,
            },
        },
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-smith-0.210.0/src/config.rs

Source (jump to first uncovered line)
//! Configuring the shape of generated Wasm modules.

use crate::InstructionKinds;
use arbitrary::{Arbitrary, Result, Unstructured};

macro_rules! define_config {
    (
        $(#[$attr:meta])*
        pub struct Config {
            $(
                $(#[$field_attr:meta])*
                pub $field:ident : $field_ty:ty = $default:expr,
            )*
        }
    ) => {
        $(#[$attr])*
        pub struct Config {
            /// The imports that may be used when generating the module.
            ///
            /// Defaults to `None` which means that any arbitrary import can be
            /// generated.
            ///
            /// To only allow specific imports, set this field to a WebAssembly
            /// module which describes the imports allowed.
            ///
            /// Note that [`Self::min_imports`] is ignored when
            /// `available_imports` are enabled.
            ///
            /// The provided value must be a valid binary encoding of a
            /// WebAssembly module. `wasm-smith` will panic if the module cannot
            /// be parsed.
            ///
            /// # Example
            ///
            /// An implementation of this method could use the `wat` crate to
            /// provide a human-readable and maintainable description:
            ///
            /// ```rust
            /// Some(wat::parse_str(r#"
            ///     (module
            ///         (import "env" "ping" (func (param i32)))
            ///         (import "env" "pong" (func (result i32)))
            ///         (import "env" "memory" (memory 1))
            ///         (import "env" "table" (table 1))
            ///         (import "env" "tag" (tag (param i32)))
            ///     )
            /// "#))
            /// # ;
            /// ```
            pub available_imports: Option<Vec<u8>>,

            /// If provided, the generated module will have exports with exactly
            /// the same names and types as those in the provided WebAssembly
            /// module. The implementation (e.g. function bodies, global
            /// initializers) of each export in the generated module will be
            /// random and unrelated to the implementation in the provided
            /// module. Only globals and functions are supported.
            ///
            ///
            /// Defaults to `None` which means arbitrary exports will be
            /// generated.
            ///
            /// To specify which exports the generated modules should have, set
            /// this field to a WebAssembly module which describes the desired
            /// exports. To generate modules with varying exports that meet some
            /// constraints, consider randomly generating the value for this
            /// field.
            ///
            /// The provided value must be a valid binary encoding of a
            /// WebAssembly module. `wasm-smith` will panic if the module cannot
            /// be parsed.
            ///
            /// # Module Limits
            ///
            /// All types, functions, globals, and exports that are needed to
            /// provide the required exports will be generated, even if it
            /// causes the resulting module to exceed the limits defined in
            /// [`Self::max_type_size`], [`Self::max_types`],
            /// [`Self::max_funcs`], [`Self::max_globals`], or
            /// [`Self::max_exports`].
            ///
            /// # Example
            ///
            /// As for [`Self::available_imports`], the `wat` crate can be used
            /// to provide an human-readable description of the desired exports:
            ///
            /// ```rust
            /// Some(wat::parse_str(r#"
            ///     (module
            ///         (func (export "foo") (param i32) (result i64) unreachable)
            ///         (global (export "bar") f32 f32.const 0)
            ///     )
            /// "#));
            /// ```
            pub exports: Option<Vec<u8>>,

            $(
                $(#[$field_attr])*
                pub $field: $field_ty,
            )*
        }

        impl Default for Config {
            fn default() -> Config {
                Config {
                    available_imports: None,
                    exports: None,

                    $(
                        $field: $default,
                    )*
                }
            }
        }

        #[cfg(feature = "_internal_cli")]
        #[doc(hidden)]
        #[derive(Clone, Debug, Default, clap::Parser, serde_derive::Deserialize)]
        #[serde(rename_all = "kebab-case")]
        pub struct InternalOptionalConfig {
            /// The imports that may be used when generating the module.
            ///
            /// When unspecified, any arbitrary import can be generated.
            ///
            /// To only allow specific imports, provide a file path of a
            /// WebAssembly module which describes the imports allowed.
            ///
            /// Note that [`Self::min_imports`] is ignored when
            /// `available_imports` are enabled.
            ///
            /// The provided value must be a valid binary encoding of a
            /// WebAssembly module. `wasm-smith` will panic if the module cannot
            /// be parsed.
            #[cfg_attr(feature = "clap", clap(long))]
            available_imports: Option<std::path::PathBuf>,

            /// If provided, the generated module will have exports with exactly
            /// the same names and types as those in the provided WebAssembly
            /// module. The implementation (e.g. function bodies, global
            /// initializers) of each export in the generated module will be
            /// random and unrelated to the implementation in the provided
            /// module. Only globals and functions are supported.
            ///
            /// Defaults to `None` which means arbitrary exports will be
            /// generated.
            ///
            /// To specify which exports the generated modules should have, set
            /// this field to a WebAssembly module which describes the desired
            /// exports. To generate modules with varying exports that meet some
            /// constraints, consider randomly generating the value for this
            /// field.
            ///
            /// The provided value must be a valid binary encoding of a
            /// WebAssembly module. `wasm-smith` will panic if the module cannot
            /// be parsed.
            ///
            /// # Module Limits
            ///
            /// All types, functions, globals, and exports that are needed to
            /// provide the required exports will be generated, even if it
            /// causes the resulting module to exceed the limits defined in
            /// [`Self::max_type_size`], [`Self::max_types`],
            /// [`Self::max_funcs`], [`Self::max_globals`], or
            /// [`Self::max_exports`].
            ///
            #[cfg_attr(feature = "clap", clap(long))]
            exports: Option<std::path::PathBuf>,

            $(
                $(#[$field_attr])*
                #[cfg_attr(feature = "clap", clap(long))]
                pub $field: Option<$field_ty>,
            )*
        }

        #[cfg(feature = "_internal_cli")]
        impl InternalOptionalConfig {
            pub fn or(self, other: Self) -> Self {
                Self {
                    available_imports: self.available_imports.or(other.available_imports),
                    exports: self.exports.or(other.exports),

                    $(
                        $field: self.$field.or(other.$field),
                    )*
                }
            }
        }

        #[cfg(feature = "_internal_cli")]
        impl TryFrom<InternalOptionalConfig> for Config {
            type Error = anyhow::Error;
            fn try_from(config: InternalOptionalConfig) -> anyhow::Result<Config> {
                let default = Config::default();
                Ok(Config {
                    available_imports: if let Some(file) = config
                        .available_imports
                        .as_ref() {
                            Some(wat::parse_file(file)?)
                        } else {
                            None
                        },
                    exports: if let Some(file) = config
                        .exports
                        .as_ref() {
                            Some(wat::parse_file(file)?)
                        } else {
                            None
                        },

                    $(
                        $field: config.$field.unwrap_or(default.$field),
                    )*
                })
            }
        }
    }
}

define_config! {
    /// Configuration for a generated module.
    ///
    /// Don't care to configure your generated modules? Just use
    /// [`Module::arbitrary`][crate::Module], which internally uses the default
    /// configuration.
    ///
    /// Want control over the shape of the module that gets generated? Create a
    /// `Config` and then pass it to [`Module::new`][crate::Module::new].
    ///
    /// # Swarm Testing
    ///
    /// You can use the `Arbitrary for Config` implementation for [swarm
    /// testing]. This will dynamically -- but still deterministically -- choose
    /// configuration options for you.
    ///
    /// [swarm testing]: https://www.cs.utah.edu/~regehr/papers/swarm12.pdf
    ///
    /// Note that we pick only *maximums*, not minimums, here because it is more
    /// complex to describe the domain of valid configs when minima are involved
    /// (`min <= max` for each variable) and minima are mostly used to ensure
    /// certain elements are present, but do not widen the range of generated
    /// Wasm modules.
    #[derive(Clone, Debug)]
    pub struct Config {
        /// Determines whether a `start` export may be included. Defaults to `true`.
        pub allow_start_export: bool = true,

        /// The kinds of instructions allowed in the generated wasm
        /// programs. Defaults to all.
        ///
        /// The categories of instructions match the categories used by the
        /// [WebAssembly
        /// specification](https://webassembly.github.io/spec/core/syntax/instructions.html);
        /// e.g., numeric, vector, control, memory, etc.
        ///
        /// Note that modifying this setting is separate from the proposal
        /// flags; that is, if `simd_enabled() == true` but
        /// `allowed_instruction()` does not include vector instructions, the
        /// generated programs will not include these instructions but could
        /// contain vector types.
        pub allowed_instructions: InstructionKinds = InstructionKinds::all(),

        /// Determines whether the bulk memory proposal is enabled for
        /// generating instructions.
        ///
        /// Defaults to `false`.
        pub bulk_memory_enabled: bool = false,

        /// Returns whether NaN values are canonicalized after all f32/f64
        /// operation. Defaults to false.
        ///
        /// This can be useful when a generated wasm module is executed in
        /// multiple runtimes which may produce different NaN values. This
        /// ensures that the generated module will always use the same NaN
        /// representation for all instructions which have visible side effects,
        /// for example writing floats to memory or float-to-int bitcast
        /// instructions.
        pub canonicalize_nans: bool = false,

        /// Returns whether we should avoid generating code that will possibly
        /// trap.
        ///
        /// For some trapping instructions, this will emit extra instructions to
        /// ensure they don't trap, while some instructions will simply be
        /// excluded.  In cases where we would run into a trap, we instead
        /// choose some arbitrary non-trapping behavior. For example, if we
        /// detect that a Load instruction would attempt to access out-of-bounds
        /// memory, we instead pretend the load succeeded and push 0 onto the
        /// stack.
        ///
        /// One type of trap that we can't currently avoid is
        /// StackOverflow. Even when `disallow_traps` is set to true, wasm-smith
        /// will eventually generate a program that infinitely recurses, causing
        /// the call stack to be exhausted.
        ///
        /// Defaults to `false`.
        pub disallow_traps: bool = false,

        /// Determines whether the exception-handling proposal is enabled for
        /// generating instructions.
        ///
        /// Defaults to `false`.
        pub exceptions_enabled: bool = false,

        /// Export all WebAssembly objects in the module. Defaults to false.
        ///
        /// This overrides [`Config::min_exports`] and [`Config::max_exports`].
        pub export_everything: bool = false,

        /// Determines whether the GC proposal is enabled when generating a Wasm
        /// module.
        ///
        /// Defaults to `false`.
        pub gc_enabled: bool = false,

        /// Determines whether the custom-page-sizes proposal is enabled when
        /// generating a Wasm module.
        ///
        /// Defaults to `false`.
        pub custom_page_sizes_enabled: bool = false,

        /// Returns whether we should generate custom sections or not. Defaults
        /// to false.
        pub generate_custom_sections: bool = false,

        /// Returns the maximal size of the `alias` section. Defaults to 1000.
        pub max_aliases: usize = 1000,

        /// The maximum number of components to use. Defaults to 10.
        ///
        /// This includes imported components.
        ///
        /// Note that this is only relevant for components.
        pub max_components: usize = 10,

        /// The maximum number of data segments to generate. Defaults to 100.
        pub max_data_segments: usize = 100,

        /// The maximum number of element segments to generate. Defaults to 100.
        pub max_element_segments: usize = 100,

        /// The maximum number of elements within a segment to
        /// generate. Defaults to 100.
        pub max_elements: usize = 100,

        /// The maximum number of exports to generate. Defaults to 100.
        pub max_exports: usize = 100,

        /// The maximum number of functions to generate. Defaults to 100.  This
        /// includes imported functions.
        pub max_funcs: usize = 100,

        /// The maximum number of globals to generate. Defaults to 100.  This
        /// includes imported globals.
        pub max_globals: usize = 100,

        /// The maximum number of imports to generate. Defaults to 100.
        pub max_imports: usize = 100,

        /// The maximum number of instances to use. Defaults to 10.
        ///
        /// This includes imported instances.
        ///
        /// Note that this is only relevant for components.
        pub max_instances: usize = 10,

        /// The maximum number of instructions to generate in a function
        /// body. Defaults to 100.
        ///
        /// Note that some additional `end`s, `else`s, and `unreachable`s may be
        /// appended to the function body to finish block scopes.
        pub max_instructions: usize = 100,

        /// The maximum number of memories to use. Defaults to 1.
        ///
        /// This includes imported memories.
        ///
        /// Note that more than one memory is in the realm of the multi-memory
        /// wasm proposal.
        pub max_memories: usize = 1,

        /// The maximum, in 64k Wasm pages, of any 32-bit memory's initial or
        /// maximum size.
        ///
        /// Defaults to 2^16.
        pub max_memory32_pages: u64 = 1 << 16,

        /// The maximum, in 64k Wasm pages, of any 64-bit memory's initial or
        /// maximum size.
        ///
        /// Defaults to 2^48.
        pub max_memory64_pages: u64 = 1 << 48,

        /// The maximum number of modules to use. Defaults to 10.
        ///
        /// This includes imported modules.
        ///
        /// Note that this is only relevant for components.
        pub max_modules: usize = 10,

        /// Returns the maximal nesting depth of modules with the component
        /// model proposal. Defaults to 10.
        pub max_nesting_depth: usize = 10,

        /// The maximum, elements, of any table's initial or maximum
        /// size. Defaults to 1 million.
        pub max_table_elements: u64 = 1_000_000,

        /// The maximum number of tables to use. Defaults to 1.
        ///
        /// This includes imported tables.
        ///
        /// Note that more than one table is in the realm of the reference types
        /// proposal.
        pub max_tables: usize = 1,

        /// The maximum number of tags to generate. Defaults to 100.
        pub max_tags: usize = 100,

        /// Returns the maximal effective size of any type generated by
        /// wasm-smith.
        ///
        /// Note that this number is roughly in units of "how many types would
        /// be needed to represent the recursive type". A function with 8
        /// parameters and 2 results would take 11 types (one for the type, 10
        /// for params/results). A module type with 2 imports and 3 exports
        /// would take 6 (module + imports + exports) plus the size of each
        /// import/export type. This is a somewhat rough measurement that is not
        /// intended to be very precise.
        ///
        /// Defaults to 1000.
        pub max_type_size: u32 = 1000,

        /// The maximum number of types to generate. Defaults to 100.
        pub max_types: usize = 100,

        /// The maximum number of values to use. Defaults to 10.
        ///
        /// This includes imported values.
        ///
        /// Note that this is irrelevant unless value model support is enabled.
        pub max_values: usize = 10,

        /// Returns whether 64-bit memories are allowed. Defaults to false.
        ///
        /// Note that this is the gate for the memory64 proposal to WebAssembly.
        pub memory64_enabled: bool = false,

        /// Whether every Wasm memory must have a maximum size
        /// specified. Defaults to `false`.
        pub memory_max_size_required: bool = false,

        /// Control the probability of generating memory offsets that are in
        /// bounds vs. potentially out of bounds.
        ///
        /// See the `MemoryOffsetChoices` struct for details.
        pub memory_offset_choices: MemoryOffsetChoices = MemoryOffsetChoices::default(),

        /// The minimum number of data segments to generate. Defaults to 0.
        pub min_data_segments: usize = 0,

        /// The minimum number of element segments to generate. Defaults to 0.
        pub min_element_segments: usize = 0,

        /// The minimum number of elements within a segment to
        /// generate. Defaults to 0.
        pub min_elements: usize = 0,

        /// The minimum number of exports to generate. Defaults to 0.
        pub min_exports: usize = 0,

        /// The minimum number of functions to generate. Defaults to 0.
        ///
        /// This includes imported functions.
        pub min_funcs: usize = 0,

        /// The minimum number of globals to generate. Defaults to 0.
        ///
        /// This includes imported globals.
        pub min_globals: usize = 0,

        /// The minimum number of imports to generate. Defaults to 0.
        ///
        /// Note that if the sum of the maximum function[^1], table, global and
        /// memory counts is less than the minimum number of imports, then it
        /// will not be possible to satisfy all constraints (because imports
        /// count against the limits for those element kinds). In that case, we
        /// strictly follow the max-constraints, and can fail to satisfy this
        /// minimum number.
        ///
        /// [^1]: the maximum number of functions is also limited by the number
        /// of function types arbitrarily chosen; strictly speaking, then, the
        /// maximum number of imports that can be created due to max-constraints
        /// is `sum(min(num_func_types, max_funcs), max_tables, max_globals,
        /// max_memories)`.
        pub min_imports: usize = 0,

        /// The minimum number of memories to use. Defaults to 0.
        ///
        /// This includes imported memories.
        pub min_memories: u32 = 0,

        /// The minimum number of tables to use. Defaults to 0.
        ///
        /// This includes imported tables.
        pub min_tables: u32 = 0,

        /// The minimum number of tags to generate. Defaults to 0.
        pub min_tags: usize = 0,

        /// The minimum number of types to generate. Defaults to 0.
        pub min_types: usize = 0,

        /// The minimum size, in bytes, of all leb-encoded integers. Defaults to
        /// 1.
        ///
        /// This is useful for ensuring that all leb-encoded integers are
        /// decoded as such rather than as simply one byte. This will forcibly
        /// extend leb integers with an over-long encoding in some locations if
        /// the size would otherwise be smaller than number returned here.
        pub min_uleb_size: u8 = 1,

        /// Determines whether the multi-value results are enabled.
        ///
        /// Defaults to `true`.
        pub multi_value_enabled: bool = true,

        /// Determines whether the reference types proposal is enabled for
        /// generating instructions.
        ///
        /// Defaults to `false`.
        pub reference_types_enabled: bool = false,

        /// Determines whether the Relaxed SIMD proposal is enabled for
        /// generating instructions.
        ///
        /// Defaults to `false`.
        pub relaxed_simd_enabled: bool = false,

        /// Determines whether the nontrapping-float-to-int-conversions propsal
        /// is enabled.
        ///
        /// Defaults to `true`.
        pub saturating_float_to_int_enabled: bool = true,

        /// Determines whether the sign-extension-ops propsal is enabled.
        ///
        /// Defaults to `true`.
        pub sign_extension_ops_enabled: bool = true,

        /// Determines whether the SIMD proposal is enabled for generating
        /// instructions.
        ///
        /// Defaults to `false`.
        pub simd_enabled: bool = false,

        /// Determines whether the tail calls proposal is enabled for generating
        /// instructions.
        ///
        /// Defaults to `false`.
        pub tail_call_enabled: bool = false,

        /// Whether every Wasm table must have a maximum size
        /// specified. Defaults to `false`.
        pub table_max_size_required: bool = false,

        /// Determines whether the threads proposal is enabled.
        ///
        /// The [threads proposal] involves shared linear memory, new atomic
        /// instructions, and new `wait` and `notify` instructions.
        ///
        /// [threads proposal]: https://github.com/WebAssembly/threads/blob/master/proposals/threads/Overview.md
        ///
        /// Defaults to `false`.
        pub threads_enabled: bool = false,

        /// Indicates whether wasm-smith is allowed to generate invalid function
        /// bodies.
        ///
        /// When enabled this option will enable taking raw bytes from the input
        /// byte stream and using them as a wasm function body. This means that
        /// the output module is not guaranteed to be valid but can help tickle
        /// various parts of validation/compilation in some circumstances as
        /// well.
        ///
        /// Defaults to `false`.
        pub allow_invalid_funcs: bool = false,
    }
}

/// This is a tuple `(a, b, c)` where
///
/// * `a / (a+b+c)` is the probability of generating a memory offset within
///   `0..memory.min_size`, i.e. an offset that is definitely in bounds of a
///   non-empty memory. (Note that if a memory is zero-sized, however, no offset
///   will ever be in bounds.)
///
/// * `b / (a+b+c)` is the probability of generating a memory offset within
///   `memory.min_size..memory.max_size`, i.e. an offset that is possibly in
///   bounds if the memory has been grown.
///
/// * `c / (a+b+c)` is the probability of generating a memory offset within the
///   range `memory.max_size..`, i.e. an offset that is definitely out of
///   bounds.
///
/// At least one of `a`, `b`, and `c` must be non-zero.
///
/// If you want to always generate memory offsets that are definitely in bounds
/// of a non-zero-sized memory, for example, you could return `(1, 0, 0)`.
///
/// The default is `(90, 9, 1)`.
#[derive(Clone, Debug)]
#[cfg_attr(feature = "serde_derive", derive(serde_derive::Deserialize))]
pub struct MemoryOffsetChoices(pub u32, pub u32, pub u32);

impl Default for MemoryOffsetChoices {
    fn default() -> Self {
        MemoryOffsetChoices(90, 9, 1)
    }
}

#[cfg(feature = "_internal_cli")]
impl std::str::FromStr for MemoryOffsetChoices {
    type Err = String;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        use std::str::FromStr;
        let mut parts = s.split(",");
        let a = parts
            .next()
            .ok_or_else(|| "need 3 comma separated values".to_string())?;
        let a = <u32 as FromStr>::from_str(a).map_err(|e| e.to_string())?;
        let b = parts
            .next()
            .ok_or_else(|| "need 3 comma separated values".to_string())?;
        let b = <u32 as FromStr>::from_str(b).map_err(|e| e.to_string())?;
        let c = parts
            .next()
            .ok_or_else(|| "need 3 comma separated values".to_string())?;
        let c = <u32 as FromStr>::from_str(c).map_err(|e| e.to_string())?;
        if parts.next().is_some() {
            return Err("found more than 3 comma separated values".to_string());
        }
        Ok(MemoryOffsetChoices(a, b, c))
    }
}

impl<'a> Arbitrary<'a> for Config {
    fn arbitrary(u: &mut Unstructured<'a>) -> Result<Self> {
        const MAX_MAXIMUM: usize = 1000;

        let reference_types_enabled: bool = u.arbitrary()?;
        let max_tables = if reference_types_enabled { 100 } else { 1 };

        Ok(Config {
            max_types: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_imports: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_tags: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_funcs: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_globals: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_exports: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_element_segments: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_elements: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_data_segments: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_instructions: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_memories: u.int_in_range(0..=100)?,
            max_tables,
            max_memory32_pages: u.int_in_range(0..=1 << 16)?,
            max_memory64_pages: u.int_in_range(0..=1 << 48)?,
            min_uleb_size: u.int_in_range(0..=5)?,
            bulk_memory_enabled: u.arbitrary()?,
            reference_types_enabled,
            simd_enabled: u.arbitrary()?,
            multi_value_enabled: u.arbitrary()?,
            max_aliases: u.int_in_range(0..=MAX_MAXIMUM)?,
            max_nesting_depth: u.int_in_range(0..=10)?,
            saturating_float_to_int_enabled: u.arbitrary()?,
            sign_extension_ops_enabled: u.arbitrary()?,
            allowed_instructions: {
                use flagset::Flags;
                let mut allowed = Vec::new();
                for kind in crate::core::InstructionKind::LIST {
                    if u.arbitrary()? {
                        allowed.push(*kind);
                    }
                }
                InstructionKinds::new(&allowed)
            },
            table_max_size_required: u.arbitrary()?,
            max_table_elements: u.int_in_range(0..=1_000_000)?,
            disallow_traps: u.arbitrary()?,

            // These fields, unlike the ones above, are less useful to set.
            // They either make weird inputs or are for features not widely
            // implemented yet so they're turned off by default.
            min_types: 0,
            min_imports: 0,
            min_tags: 0,
            min_funcs: 0,
            min_globals: 0,
            min_exports: 0,
            min_element_segments: 0,
            min_elements: 0,
            min_data_segments: 0,
            min_memories: 0,
            min_tables: 0,
            memory_max_size_required: false,
            max_instances: 0,
            max_modules: 0,
            max_components: 0,
            max_values: 0,
            memory_offset_choices: MemoryOffsetChoices::default(),
            allow_start_export: true,
            relaxed_simd_enabled: false,
            exceptions_enabled: false,
            memory64_enabled: false,
            max_type_size: 1000,
            canonicalize_nans: false,
            available_imports: None,
            exports: None,
            threads_enabled: false,
            export_everything: false,
            tail_call_enabled: false,
            gc_enabled: false,
            custom_page_sizes_enabled: false,
            generate_custom_sections: false,
            allow_invalid_funcs: false,
        })
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-smith-0.210.0/src/core.rs

Source (jump to first uncovered line)
//! Generating arbitary core Wasm modules.

mod code_builder;
pub(crate) mod encode;
mod terminate;

use crate::{arbitrary_loop, limited_string, unique_string, Config};
use arbitrary::{Arbitrary, Result, Unstructured};
use code_builder::CodeBuilderAllocations;
use flagset::{flags, FlagSet};
use std::collections::{HashMap, HashSet};
use std::fmt;
use std::mem;
use std::ops::Range;
use std::rc::Rc;
use std::str::{self, FromStr};
use wasm_encoder::{
    ArrayType, BlockType, ConstExpr, ExportKind, FieldType, HeapType, RefType, StorageType,
    StructType, ValType,
};
pub(crate) use wasm_encoder::{GlobalType, MemoryType, TableType};

// NB: these constants are used to control the rate at which various events
// occur. For more information see where these constants are used. Their values
// are somewhat random in the sense that they're not scientifically determined
// or anything like that, I just threw a bunch of random data at wasm-smith and
// measured various rates of ooms/traps/etc and adjusted these so abnormal
// events were ~1% of the time.
const CHANCE_OFFSET_INBOUNDS: usize = 10; // bigger = less traps
const CHANCE_SEGMENT_ON_EMPTY: usize = 10; // bigger = less traps
const PCT_INBOUNDS: f64 = 0.995; // bigger = less traps

type Instruction = wasm_encoder::Instruction<'static>;

/// A pseudo-random WebAssembly module.
///
/// Construct instances of this type (with default configuration) with [the
/// `Arbitrary`
/// trait](https://docs.rs/arbitrary/*/arbitrary/trait.Arbitrary.html).
///
/// ## Configuring Generated Modules
///
/// To configure the shape of generated module, create a
/// [`Config`][crate::Config] and then call [`Module::new`][crate::Module::new]
/// with it.
pub struct Module {
    config: Config,
    duplicate_imports_behavior: DuplicateImportsBehavior,
    valtypes: Vec<ValType>,

    /// All types locally defined in this module (available in the type index
    /// space).
    types: Vec<SubType>,

    /// Non-overlapping ranges within `types` that belong to the same rec
    /// group. All of `types` is covered by these ranges. When GC is not
    /// enabled, these are all single-element ranges.
    rec_groups: Vec<Range<usize>>,

    /// A map from a super type to all of its sub types.
    super_to_sub_types: HashMap<u32, Vec<u32>>,

    /// Indices within `types` that are not final types.
    can_subtype: Vec<u32>,

    /// Whether we should encode a types section, even if `self.types` is empty.
    should_encode_types: bool,

    /// All of this module's imports. These don't have their own index space,
    /// but instead introduce entries to each imported entity's associated index
    /// space.
    imports: Vec<Import>,

    /// Whether we should encode an imports section, even if `self.imports` is
    /// empty.
    should_encode_imports: bool,

    /// Indices within `types` that are array types.
    array_types: Vec<u32>,

    /// Indices within `types` that are function types.
    func_types: Vec<u32>,

    /// Indices within `types that are struct types.
    struct_types: Vec<u32>,

    /// Number of imported items into this module.
    num_imports: usize,

    /// The number of tags defined in this module (not imported or
    /// aliased).
    num_defined_tags: usize,

    /// The number of functions defined in this module (not imported or
    /// aliased).
    num_defined_funcs: usize,

    /// Initialization expressions for all defined tables in this module.
    defined_tables: Vec<Option<ConstExpr>>,

    /// The number of memories defined in this module (not imported or
    /// aliased).
    num_defined_memories: usize,

    /// The indexes and initialization expressions of globals defined in this
    /// module.
    defined_globals: Vec<(u32, ConstExpr)>,

    /// All tags available to this module, sorted by their index. The list
    /// entry is the type of each tag.
    tags: Vec<TagType>,

    /// All functions available to this module, sorted by their index. The list
    /// entry points to the index in this module where the function type is
    /// defined (if available) and provides the type of the function.
    funcs: Vec<(u32, Rc<FuncType>)>,

    /// All tables available to this module, sorted by their index. The list
    /// entry is the type of each table.
    tables: Vec<TableType>,

    /// All globals available to this module, sorted by their index. The list
    /// entry is the type of each global.
    globals: Vec<GlobalType>,

    /// All memories available to this module, sorted by their index. The list
    /// entry is the type of each memory.
    memories: Vec<MemoryType>,

    exports: Vec<(String, ExportKind, u32)>,
    start: Option<u32>,
    elems: Vec<ElementSegment>,
    code: Vec<Code>,
    data: Vec<DataSegment>,

    /// The predicted size of the effective type of this module, based on this
    /// module's size of the types of imports/exports.
    type_size: u32,

    /// Names currently exported from this module.
    export_names: HashSet<String>,

    /// Reusable buffer in `self.arbitrary_const_expr` to amortize the cost of
    /// allocation.
    const_expr_choices: Vec<Box<dyn Fn(&mut Unstructured, ValType) -> Result<ConstExpr>>>,

    /// What the maximum type index that can be referenced is.
    max_type_limit: MaxTypeLimit,

    /// Some known-interesting values, such as powers of two, values just before
    /// or just after a memory size, etc...
    interesting_values32: Vec<u32>,
    interesting_values64: Vec<u64>,
}

impl<'a> Arbitrary<'a> for Module {
    fn arbitrary(u: &mut Unstructured<'a>) -> Result<Self> {
        Module::new(Config::default(), u)
    }
}

impl fmt::Debug for Module {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Module")
            .field("config", &self.config)
            .field(&"...", &"...")
            .finish()
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum DuplicateImportsBehavior {
    Allowed,
    Disallowed,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum MaxTypeLimit {
    ModuleTypes,
    Num(u32),
}

impl Module {
    /// Returns a reference to the internal configuration.
    pub fn config(&self) -> &Config {
        &self.config
    }

    /// Creates a new `Module` with the specified `config` for
    /// configuration and `Unstructured` for the DNA of this module.
    pub fn new(config: Config, u: &mut Unstructured<'_>) -> Result<Self> {
        Self::new_internal(config, u, DuplicateImportsBehavior::Allowed)
    }

    pub(crate) fn new_internal(
        config: Config,
        u: &mut Unstructured<'_>,
        duplicate_imports_behavior: DuplicateImportsBehavior,
    ) -> Result<Self> {
        let mut module = Module::empty(config, duplicate_imports_behavior);
        module.build(u)?;
        Ok(module)
    }

    fn empty(config: Config, duplicate_imports_behavior: DuplicateImportsBehavior) -> Self {
        Module {
            config,
            duplicate_imports_behavior,
            valtypes: Vec::new(),
            types: Vec::new(),
            rec_groups: Vec::new(),
            can_subtype: Vec::new(),
            super_to_sub_types: HashMap::new(),
            should_encode_types: false,
            imports: Vec::new(),
            should_encode_imports: false,
            array_types: Vec::new(),
            func_types: Vec::new(),
            struct_types: Vec::new(),
            num_imports: 0,
            num_defined_tags: 0,
            num_defined_funcs: 0,
            defined_tables: Vec::new(),
            num_defined_memories: 0,
            defined_globals: Vec::new(),
            tags: Vec::new(),
            funcs: Vec::new(),
            tables: Vec::new(),
            globals: Vec::new(),
            memories: Vec::new(),
            exports: Vec::new(),
            start: None,
            elems: Vec::new(),
            code: Vec::new(),
            data: Vec::new(),
            type_size: 0,
            export_names: HashSet::new(),
            const_expr_choices: Vec::new(),
            max_type_limit: MaxTypeLimit::ModuleTypes,
            interesting_values32: Vec::new(),
            interesting_values64: Vec::new(),
        }
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub(crate) struct SubType {
    pub(crate) is_final: bool,
    pub(crate) supertype: Option<u32>,
    pub(crate) composite_type: CompositeType,
}

impl SubType {
    fn unwrap_struct(&self) -> &StructType {
        self.composite_type.unwrap_struct()
    }

    fn unwrap_func(&self) -> &Rc<FuncType> {
        self.composite_type.unwrap_func()
    }

    fn unwrap_array(&self) -> &ArrayType {
        self.composite_type.unwrap_array()
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub(crate) enum CompositeType {
    Array(ArrayType),
    Func(Rc<FuncType>),
    Struct(StructType),
}

impl CompositeType {
    fn unwrap_struct(&self) -> &StructType {
        match self {
            CompositeType::Struct(s) => s,
            _ => panic!("not a struct"),
        }
    }

    fn unwrap_func(&self) -> &Rc<FuncType> {
        match self {
            CompositeType::Func(f) => f,
            _ => panic!("not a func"),
        }
    }

    fn unwrap_array(&self) -> &ArrayType {
        match self {
            CompositeType::Array(a) => a,
            _ => panic!("not an array"),
        }
    }
}

/// A function signature.
#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub(crate) struct FuncType {
    /// Types of the parameter values.
    pub(crate) params: Vec<ValType>,
    /// Types of the result values.
    pub(crate) results: Vec<ValType>,
}

/// An import of an entity provided externally or by a component.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub(crate) struct Import {
    /// The name of the module providing this entity.
    pub(crate) module: String,
    /// The name of the entity.
    pub(crate) field: String,
    /// The type of this entity.
    pub(crate) entity_type: EntityType,
}

/// Type of an entity.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub(crate) enum EntityType {
    /// A global entity.
    Global(GlobalType),
    /// A table entity.
    Table(TableType),
    /// A memory entity.
    Memory(MemoryType),
    /// A tag entity.
    Tag(TagType),
    /// A function entity.
    Func(u32, Rc<FuncType>),
}

/// Type of a tag.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub(crate) struct TagType {
    /// Index of the function type.
    func_type_idx: u32,
    /// Type of the function.
    func_type: Rc<FuncType>,
}

#[derive(Debug)]
struct ElementSegment {
    kind: ElementKind,
    ty: RefType,
    items: Elements,
}

#[derive(Debug)]
enum ElementKind {
    Passive,
    Declared,
    Active {
        table: Option<u32>, // None == table 0 implicitly
        offset: Offset,
    },
}

#[derive(Debug)]
enum Elements {
    Functions(Vec<u32>),
    Expressions(Vec<ConstExpr>),
}

#[derive(Debug)]
struct Code {
    locals: Vec<ValType>,
    instructions: Instructions,
}

#[derive(Debug)]
enum Instructions {
    Generated(Vec<Instruction>),
    Arbitrary(Vec<u8>),
}

#[derive(Debug)]
struct DataSegment {
    kind: DataSegmentKind,
    init: Vec<u8>,
}

#[derive(Debug)]
enum DataSegmentKind {
    Passive,
    Active { memory_index: u32, offset: Offset },
}

#[derive(Debug)]
pub(crate) enum Offset {
    Const32(i32),
    Const64(i64),
    Global(u32),
}

impl Module {
    fn build(&mut self, u: &mut Unstructured) -> Result<()> {
        self.valtypes = configured_valtypes(&self.config);

        // We attempt to figure out our available imports *before* creating the types section here,
        // because the types for the imports are already well-known (specified by the user) and we
        // must have those populated for all function/etc. imports, no matter what.
        //
        // This can affect the available capacity for types and such.
        if self.arbitrary_imports_from_available(u)? {
            self.arbitrary_types(u)?;
        } else {
            self.arbitrary_types(u)?;
            self.arbitrary_imports(u)?;
        }

        self.should_encode_imports = !self.imports.is_empty() || u.arbitrary()?;

        self.arbitrary_tags(u)?;
        self.arbitrary_funcs(u)?;
        self.arbitrary_tables(u)?;
        self.arbitrary_memories(u)?;
        self.arbitrary_globals(u)?;
        if !self.required_exports(u)? {
            self.arbitrary_exports(u)?;
        };
        self.should_encode_types = !self.types.is_empty() || u.arbitrary()?;
        self.arbitrary_start(u)?;
        self.arbitrary_elems(u)?;
        self.arbitrary_data(u)?;
        self.arbitrary_code(u)?;
        Ok(())
    }

    #[inline]
    fn val_type_is_sub_type(&self, a: ValType, b: ValType) -> bool {
        match (a, b) {
            (a, b) if a == b => true,
            (ValType::Ref(a), ValType::Ref(b)) => self.ref_type_is_sub_type(a, b),
            _ => false,
        }
    }

    /// Is `a` a subtype of `b`?
    fn ref_type_is_sub_type(&self, a: RefType, b: RefType) -> bool {
        if a == b {
            return true;
        }

        if a.nullable && !b.nullable {
            return false;
        }

        self.heap_type_is_sub_type(a.heap_type, b.heap_type)
    }

    fn heap_type_is_sub_type(&self, a: HeapType, b: HeapType) -> bool {
        use HeapType as HT;
        match (a, b) {
            (a, b) if a == b => true,

            (HT::Eq | HT::I31 | HT::Struct | HT::Array | HT::None, HT::Any) => true,
            (HT::I31 | HT::Struct | HT::Array | HT::None, HT::Eq) => true,
            (HT::NoExtern, HT::Extern) => true,
            (HT::NoFunc, HT::Func) => true,
            (HT::None, HT::I31 | HT::Array | HT::Struct) => true,

            (HT::Concrete(a), HT::Eq | HT::Any) => matches!(
                self.ty(a).composite_type,
                CompositeType::Array(_) | CompositeType::Struct(_)
            ),

            (HT::Concrete(a), HT::Struct) => {
                matches!(self.ty(a).composite_type, CompositeType::Struct(_))
            }

            (HT::Concrete(a), HT::Array) => {
                matches!(self.ty(a).composite_type, CompositeType::Array(_))
            }

            (HT::Concrete(a), HT::Func) => {
                matches!(self.ty(a).composite_type, CompositeType::Func(_))
            }

            (HT::Concrete(mut a), HT::Concrete(b)) => loop {
                if a == b {
                    return true;
                }
                if let Some(supertype) = self.ty(a).supertype {
                    a = supertype;
                } else {
                    return false;
                }
            },

            (HT::None, HT::Concrete(b)) => matches!(
                self.ty(b).composite_type,
                CompositeType::Array(_) | CompositeType::Struct(_)
            ),

            (HT::NoFunc, HT::Concrete(b)) => {
                matches!(self.ty(b).composite_type, CompositeType::Func(_))
            }

            (HT::NoExn, HT::Exn) => true,

            // Nothing else matches. (Avoid full wildcard matches so that
            // adding/modifying variants is easier in the future.)
            (HT::Concrete(_), _)
            | (HT::Func, _)
            | (HT::Extern, _)
            | (HT::Any, _)
            | (HT::None, _)
            | (HT::NoExtern, _)
            | (HT::NoFunc, _)
            | (HT::Eq, _)
            | (HT::Struct, _)
            | (HT::Array, _)
            | (HT::I31, _)
            | (HT::Exn, _)
            | (HT::NoExn, _) => false,
        }
    }

    fn arbitrary_types(&mut self, u: &mut Unstructured) -> Result<()> {
        assert!(self.config.min_types <= self.config.max_types);
        while self.types.len() < self.config.min_types {
            self.arbitrary_rec_group(u)?;
        }
        while self.types.len() < self.config.max_types {
            let keep_going = u.arbitrary().unwrap_or(false);
            if !keep_going {
                break;
            }
            self.arbitrary_rec_group(u)?;
        }
        Ok(())
    }

    fn add_type(&mut self, ty: SubType) -> u32 {
        let index = u32::try_from(self.types.len()).unwrap();

        if let Some(supertype) = ty.supertype {
            self.super_to_sub_types
                .entry(supertype)
                .or_default()
                .push(index);
        }

        let list = match &ty.composite_type {
            CompositeType::Array(_) => &mut self.array_types,
            CompositeType::Func(_) => &mut self.func_types,
            CompositeType::Struct(_) => &mut self.struct_types,
        };
        list.push(index);

        if !ty.is_final {
            self.can_subtype.push(index);
        }

        self.types.push(ty);
        index
    }

    fn arbitrary_rec_group(&mut self, u: &mut Unstructured) -> Result<()> {
        let rec_group_start = self.types.len();

        assert!(matches!(self.max_type_limit, MaxTypeLimit::ModuleTypes));

        if self.config.gc_enabled {
            // With small probability, clone an existing rec group.
            if self.clonable_rec_groups().next().is_some() && u.ratio(1, u8::MAX)? {
                return self.clone_rec_group(u);
            }

            // Otherwise, create a new rec group with multiple types inside.
            let max_rec_group_size = self.config.max_types - self.types.len();
            let rec_group_size = u.int_in_range(0..=max_rec_group_size)?;
            let type_ref_limit = u32::try_from(self.types.len() + rec_group_size).unwrap();
            self.max_type_limit = MaxTypeLimit::Num(type_ref_limit);
            for _ in 0..rec_group_size {
                let ty = self.arbitrary_sub_type(u)?;
                self.add_type(ty);
            }
        } else {
            let type_ref_limit = u32::try_from(self.types.len()).unwrap();
            self.max_type_limit = MaxTypeLimit::Num(type_ref_limit);
            let ty = self.arbitrary_sub_type(u)?;
            self.add_type(ty);
        }

        self.max_type_limit = MaxTypeLimit::ModuleTypes;

        self.rec_groups.push(rec_group_start..self.types.len());
        Ok(())
    }

    /// Returns an iterator of rec groups that we could currently clone while
    /// still staying within the max types limit.
    fn clonable_rec_groups(&self) -> impl Iterator<Item = Range<usize>> + '_ {
        self.rec_groups
            .iter()
            .filter(|r| r.end - r.start <= self.config.max_types.saturating_sub(self.types.len()))
            .cloned()
    }

    fn clone_rec_group(&mut self, u: &mut Unstructured) -> Result<()> {
        // NB: this does *not* guarantee that the cloned rec group will
        // canonicalize the same as the original rec group and be
        // deduplicated. That would reqiure a second pass over the cloned types
        // to rewrite references within the original rec group to be references
        // into the new rec group. That might make sense to do one day, but for
        // now we don't do it. That also means that we can't mark the new types
        // as "subtypes" of the old types and vice versa.
        let candidates: Vec<_> = self.clonable_rec_groups().collect();
        let group = u.choose(&candidates)?.clone();
        let new_rec_group_start = self.types.len();
        for index in group {
            let orig_ty_index = u32::try_from(index).unwrap();
            let ty = self.ty(orig_ty_index).clone();
            self.add_type(ty);
        }
        self.rec_groups.push(new_rec_group_start..self.types.len());
        Ok(())
    }

    fn arbitrary_sub_type(&mut self, u: &mut Unstructured) -> Result<SubType> {
        if !self.config.gc_enabled {
            return Ok(SubType {
                is_final: true,
                supertype: None,
                composite_type: CompositeType::Func(self.arbitrary_func_type(u)?),
            });
        }

        if !self.can_subtype.is_empty() && u.ratio(1, 32_u8)? {
            self.arbitrary_sub_type_of_super_type(u)
        } else {
            Ok(SubType {
                is_final: u.arbitrary()?,
                supertype: None,
                composite_type: self.arbitrary_composite_type(u)?,
            })
        }
    }

    fn arbitrary_sub_type_of_super_type(&mut self, u: &mut Unstructured) -> Result<SubType> {
        let supertype = *u.choose(&self.can_subtype)?;
        let mut composite_type = self.types[usize::try_from(supertype).unwrap()]
            .composite_type
            .clone();
        match &mut composite_type {
            CompositeType::Array(a) => {
                a.0 = self.arbitrary_matching_field_type(u, a.0)?;
            }
            CompositeType::Func(f) => {
                *f = self.arbitrary_matching_func_type(u, f)?;
            }
            CompositeType::Struct(s) => {
                *s = self.arbitrary_matching_struct_type(u, s)?;
            }
        }
        Ok(SubType {
            is_final: u.arbitrary()?,
            supertype: Some(supertype),
            composite_type,
        })
    }

    fn arbitrary_matching_struct_type(
        &mut self,
        u: &mut Unstructured,
        ty: &StructType,
    ) -> Result<StructType> {
        let len_extra_fields = u.int_in_range(0..=5)?;
        let mut fields = Vec::with_capacity(ty.fields.len() + len_extra_fields);
        for field in ty.fields.iter() {
            fields.push(self.arbitrary_matching_field_type(u, *field)?);
        }
        for _ in 0..len_extra_fields {
            fields.push(self.arbitrary_field_type(u)?);
        }
        Ok(StructType {
            fields: fields.into_boxed_slice(),
        })
    }

    fn arbitrary_matching_field_type(
        &mut self,
        u: &mut Unstructured,
        ty: FieldType,
    ) -> Result<FieldType> {
        Ok(FieldType {
            element_type: self.arbitrary_matching_storage_type(u, ty.element_type)?,
            mutable: if ty.mutable { u.arbitrary()? } else { false },
        })
    }

    fn arbitrary_matching_storage_type(
        &mut self,
        u: &mut Unstructured,
        ty: StorageType,
    ) -> Result<StorageType> {
        match ty {
            StorageType::I8 => Ok(StorageType::I8),
            StorageType::I16 => Ok(StorageType::I16),
            StorageType::Val(ty) => Ok(StorageType::Val(self.arbitrary_matching_val_type(u, ty)?)),
        }
    }

    fn arbitrary_matching_val_type(
        &mut self,
        u: &mut Unstructured,
        ty: ValType,
    ) -> Result<ValType> {
        match ty {
            ValType::I32 => Ok(ValType::I32),
            ValType::I64 => Ok(ValType::I64),
            ValType::F32 => Ok(ValType::F32),
            ValType::F64 => Ok(ValType::F64),
            ValType::V128 => Ok(ValType::V128),
            ValType::Ref(ty) => Ok(ValType::Ref(self.arbitrary_matching_ref_type(u, ty)?)),
        }
    }

    fn arbitrary_matching_ref_type(&self, u: &mut Unstructured, ty: RefType) -> Result<RefType> {
        Ok(RefType {
            nullable: ty.nullable,
            heap_type: self.arbitrary_matching_heap_type(u, ty.heap_type)?,
        })
    }

    fn arbitrary_matching_heap_type(&self, u: &mut Unstructured, ty: HeapType) -> Result<HeapType> {
        if !self.config.gc_enabled {
            return Ok(ty);
        }
        use HeapType as HT;
        let mut choices = vec![ty];
        match ty {
            HT::Any => {
                choices.extend([HT::Eq, HT::Struct, HT::Array, HT::I31, HT::None]);
                choices.extend(self.array_types.iter().copied().map(HT::Concrete));
                choices.extend(self.struct_types.iter().copied().map(HT::Concrete));
            }
            HT::Eq => {
                choices.extend([HT::Struct, HT::Array, HT::I31, HT::None]);
                choices.extend(self.array_types.iter().copied().map(HT::Concrete));
                choices.extend(self.struct_types.iter().copied().map(HT::Concrete));
            }
            HT::Struct => {
                choices.extend([HT::Struct, HT::None]);
                choices.extend(self.struct_types.iter().copied().map(HT::Concrete));
            }
            HT::Array => {
                choices.extend([HT::Array, HT::None]);
                choices.extend(self.array_types.iter().copied().map(HT::Concrete));
            }
            HT::I31 => {
                choices.push(HT::None);
            }
            HT::Concrete(idx) => {
                if let Some(subs) = self.super_to_sub_types.get(&idx) {
                    choices.extend(subs.iter().copied().map(HT::Concrete));
                }
                match self
                    .types
                    .get(usize::try_from(idx).unwrap())
                    .map(|ty| &ty.composite_type)
                {
                    Some(CompositeType::Array(_)) | Some(CompositeType::Struct(_)) => {
                        choices.push(HT::None)
                    }
                    Some(CompositeType::Func(_)) => choices.push(HT::NoFunc),
                    None => {
                        // The referenced type might be part of this same rec
                        // group we are currently generating, but not generated
                        // yet. In this case, leave `choices` as it is, and we
                        // will just end up choosing the original type again
                        // down below, which is fine.
                    }
                }
            }
            HT::Func => {
                choices.extend(self.func_types.iter().copied().map(HT::Concrete));
                choices.push(HT::NoFunc);
            }
            HT::Extern => {
                choices.push(HT::NoExtern);
            }
            HT::Exn | HT::NoExn | HT::None | HT::NoExtern | HT::NoFunc => {}
        }
        Ok(*u.choose(&choices)?)
    }

    fn arbitrary_matching_func_type(
        &mut self,
        u: &mut Unstructured,
        ty: &FuncType,
    ) -> Result<Rc<FuncType>> {
        // Note: parameters are contravariant, results are covariant. See
        // https://github.com/bytecodealliance/wasm-tools/blob/0616ef196a183cf137ee06b4a5993b7d590088bf/crates/wasmparser/src/readers/core/types/matches.rs#L137-L174
        // for details.
        let mut params = Vec::with_capacity(ty.params.len());
        for param in &ty.params {
            params.push(self.arbitrary_super_type_of_val_type(u, *param)?);
        }
        let mut results = Vec::with_capacity(ty.results.len());
        for result in &ty.results {
            results.push(self.arbitrary_matching_val_type(u, *result)?);
        }
        Ok(Rc::new(FuncType { params, results }))
    }

    fn arbitrary_super_type_of_val_type(
        &mut self,
        u: &mut Unstructured,
        ty: ValType,
    ) -> Result<ValType> {
        match ty {
            ValType::I32 => Ok(ValType::I32),
            ValType::I64 => Ok(ValType::I64),
            ValType::F32 => Ok(ValType::F32),
            ValType::F64 => Ok(ValType::F64),
            ValType::V128 => Ok(ValType::V128),
            ValType::Ref(ty) => Ok(ValType::Ref(self.arbitrary_super_type_of_ref_type(u, ty)?)),
        }
    }

    fn arbitrary_super_type_of_ref_type(
        &self,
        u: &mut Unstructured,
        ty: RefType,
    ) -> Result<RefType> {
        Ok(RefType {
            // TODO: For now, only create allow nullable reference
            // types. Eventually we should support non-nullable reference types,
            // but this means that we will also need to recognize when it is
            // impossible to create an instance of the reference (eg `(ref
            // nofunc)` has no instances, and self-referential types that
            // contain a non-null self-reference are also impossible to create).
            nullable: true,
            heap_type: self.arbitrary_super_type_of_heap_type(u, ty.heap_type)?,
        })
    }

    fn arbitrary_super_type_of_heap_type(
        &self,
        u: &mut Unstructured,
        ty: HeapType,
    ) -> Result<HeapType> {
        if !self.config.gc_enabled {
            return Ok(ty);
        }
        use HeapType as HT;
        let mut choices = vec![ty];
        match ty {
            HT::None => {
                choices.extend([HT::Any, HT::Eq, HT::Struct, HT::Array, HT::I31]);
                choices.extend(self.array_types.iter().copied().map(HT::Concrete));
                choices.extend(self.struct_types.iter().copied().map(HT::Concrete));
            }
            HT::NoExtern => {
                choices.push(HT::Extern);
            }
            HT::NoFunc => {
                choices.extend(self.func_types.iter().copied().map(HT::Concrete));
                choices.push(HT::Func);
            }
            HT::NoExn => {
                choices.push(HT::Exn);
            }
            HT::Concrete(mut idx) => {
                match &self
                    .types
                    .get(usize::try_from(idx).unwrap())
                    .map(|ty| &ty.composite_type)
                {
                    Some(CompositeType::Array(_)) => {
                        choices.extend([HT::Any, HT::Eq, HT::Array]);
                    }
                    Some(CompositeType::Func(_)) => {
                        choices.push(HT::Func);
                    }
                    Some(CompositeType::Struct(_)) => {
                        choices.extend([HT::Any, HT::Eq, HT::Struct]);
                    }
                    None => {
                        // Same as in `arbitrary_matching_heap_type`: this was a
                        // forward reference to a concrete type that is part of
                        // this same rec group we are generating right now, and
                        // therefore we haven't generated that type yet. Just
                        // leave `choices` as it is and we will choose the
                        // original type again down below.
                    }
                }
                while let Some(supertype) = self
                    .types
                    .get(usize::try_from(idx).unwrap())
                    .and_then(|ty| ty.supertype)
                {
                    choices.push(HT::Concrete(supertype));
                    idx = supertype;
                }
            }
            HT::Struct | HT::Array | HT::I31 => {
                choices.extend([HT::Any, HT::Eq]);
            }
            HT::Eq => {
                choices.push(HT::Any);
            }
            HT::Exn | HT::Any | HT::Func | HT::Extern => {}
        }
        Ok(*u.choose(&choices)?)
    }

    fn arbitrary_composite_type(&mut self, u: &mut Unstructured) -> Result<CompositeType> {
        if !self.config.gc_enabled {
            return Ok(CompositeType::Func(self.arbitrary_func_type(u)?));
        }

        match u.int_in_range(0..=2)? {
            0 => Ok(CompositeType::Array(ArrayType(
                self.arbitrary_field_type(u)?,
            ))),
            1 => Ok(CompositeType::Func(self.arbitrary_func_type(u)?)),
            2 => Ok(CompositeType::Struct(self.arbitrary_struct_type(u)?)),
            _ => unreachable!(),
        }
    }

    fn arbitrary_struct_type(&mut self, u: &mut Unstructured) -> Result<StructType> {
        let len = u.int_in_range(0..=20)?;
        let mut fields = Vec::with_capacity(len);
        for _ in 0..len {
            fields.push(self.arbitrary_field_type(u)?);
        }
        Ok(StructType {
            fields: fields.into_boxed_slice(),
        })
    }

    fn arbitrary_field_type(&mut self, u: &mut Unstructured) -> Result<FieldType> {
        Ok(FieldType {
            element_type: self.arbitrary_storage_type(u)?,
            mutable: u.arbitrary()?,
        })
    }

    fn arbitrary_storage_type(&mut self, u: &mut Unstructured) -> Result<StorageType> {
        match u.int_in_range(0..=2)? {
            0 => Ok(StorageType::I8),
            1 => Ok(StorageType::I16),
            2 => Ok(StorageType::Val(self.arbitrary_valtype(u)?)),
            _ => unreachable!(),
        }
    }

    fn arbitrary_ref_type(&self, u: &mut Unstructured) -> Result<RefType> {
        if !self.config.reference_types_enabled {
            return Ok(RefType::FUNCREF);
        }
        Ok(RefType {
            nullable: true,
            heap_type: self.arbitrary_heap_type(u)?,
        })
    }

    fn arbitrary_heap_type(&self, u: &mut Unstructured) -> Result<HeapType> {
        assert!(self.config.reference_types_enabled);

        let concrete_type_limit = match self.max_type_limit {
            MaxTypeLimit::Num(n) => n,
            MaxTypeLimit::ModuleTypes => u32::try_from(self.types.len()).unwrap(),
        };

        if self.config.gc_enabled && concrete_type_limit > 0 && u.arbitrary()? {
            let idx = u.int_in_range(0..=concrete_type_limit - 1)?;
            return Ok(HeapType::Concrete(idx));
        }

        let mut choices = vec![HeapType::Func, HeapType::Extern];
        if self.config.exceptions_enabled {
            choices.push(HeapType::Exn);
        }
        if self.config.gc_enabled {
            choices.extend(
                [
                    HeapType::Any,
                    HeapType::None,
                    HeapType::NoExtern,
                    HeapType::NoFunc,
                    HeapType::Eq,
                    HeapType::Struct,
                    HeapType::Array,
                    HeapType::I31,
                ]
                .iter()
                .copied(),
            );
        }
        u.choose(&choices).copied()
    }

    fn arbitrary_func_type(&mut self, u: &mut Unstructured) -> Result<Rc<FuncType>> {
        let mut params = vec![];
        let mut results = vec![];
        let max_params = 20;
        arbitrary_loop(u, 0, max_params, |u| {
            params.push(self.arbitrary_valtype(u)?);
            Ok(true)
        })?;
        let max_results = if self.config.multi_value_enabled {
            max_params
        } else {
            1
        };
        arbitrary_loop(u, 0, max_results, |u| {
            results.push(self.arbitrary_valtype(u)?);
            Ok(true)
        })?;
        Ok(Rc::new(FuncType { params, results }))
    }

    fn can_add_local_or_import_tag(&self) -> bool {
        self.config.exceptions_enabled
            && self.has_tag_func_types()
            && self.tags.len() < self.config.max_tags
    }

    fn can_add_local_or_import_func(&self) -> bool {
        !self.func_types.is_empty() && self.funcs.len() < self.config.max_funcs
    }

    fn can_add_local_or_import_table(&self) -> bool {
        self.tables.len() < self.config.max_tables
    }

    fn can_add_local_or_import_global(&self) -> bool {
        self.globals.len() < self.config.max_globals
    }

    fn can_add_local_or_import_memory(&self) -> bool {
        self.memories.len() < self.config.max_memories
    }

    fn arbitrary_imports(&mut self, u: &mut Unstructured) -> Result<()> {
        if self.config.max_type_size < self.type_size {
            return Ok(());
        }

        let mut import_strings = HashSet::new();
        let mut choices: Vec<fn(&mut Unstructured, &mut Module) -> Result<EntityType>> =
            Vec::with_capacity(5);
        let min = self.config.min_imports.saturating_sub(self.num_imports);
        let max = self.config.max_imports.saturating_sub(self.num_imports);
        arbitrary_loop(u, min, max, |u| {
            choices.clear();
            if self.can_add_local_or_import_tag() {
                choices.push(|u, m| {
                    let ty = m.arbitrary_tag_type(u)?;
                    Ok(EntityType::Tag(ty))
                });
            }
            if self.can_add_local_or_import_func() {
                choices.push(|u, m| {
                    let idx = *u.choose(&m.func_types)?;
                    let ty = m.func_type(idx).clone();
                    Ok(EntityType::Func(idx, ty))
                });
            }
            if self.can_add_local_or_import_global() {
                choices.push(|u, m| {
                    let ty = m.arbitrary_global_type(u)?;
                    Ok(EntityType::Global(ty))
                });
            }
            if self.can_add_local_or_import_memory() {
                choices.push(|u, m| {
                    let ty = arbitrary_memtype(u, m.config())?;
                    Ok(EntityType::Memory(ty))
                });
            }
            if self.can_add_local_or_import_table() {
                choices.push(|u, m| {
                    let ty = arbitrary_table_type(u, m.config(), Some(m))?;
                    Ok(EntityType::Table(ty))
                });
            }

            if choices.is_empty() {
                // We are out of choices. If we have not have reached the
                // minimum yet, then we have no way to satisfy the constraint,
                // but we follow max-constraints before the min-import
                // constraint.
                return Ok(false);
            }

            // Generate a type to import, but only actually add the item if the
            // type size budget allows us to.
            let f = u.choose(&choices)?;
            let entity_type = f(u, self)?;
            let budget = self.config.max_type_size - self.type_size;
            if entity_type.size() + 1 > budget {
                return Ok(false);
            }
            self.type_size += entity_type.size() + 1;

            // Generate an arbitrary module/name pair to name this import.
            let mut import_pair = unique_import_strings(1_000, u)?;
            if self.duplicate_imports_behavior == DuplicateImportsBehavior::Disallowed {
                while import_strings.contains(&import_pair) {
                    use std::fmt::Write;
                    write!(&mut import_pair.1, "{}", import_strings.len()).unwrap();
                }
                import_strings.insert(import_pair.clone());
            }
            let (module, field) = import_pair;

            // Once our name is determined, then we push the typed item into the
            // appropriate namespace.
            match &entity_type {
                EntityType::Tag(ty) => self.tags.push(ty.clone()),
                EntityType::Func(idx, ty) => self.funcs.push((*idx, ty.clone())),
                EntityType::Global(ty) => self.globals.push(*ty),
                EntityType::Table(ty) => self.tables.push(*ty),
                EntityType::Memory(ty) => self.memories.push(*ty),
            }

            self.num_imports += 1;
            self.imports.push(Import {
                module,
                field,
                entity_type,
            });
            Ok(true)
        })?;

        Ok(())
    }

    /// Generate some arbitrary imports from the list of available imports.
    ///
    /// Returns `true` if there was a list of available imports
    /// configured. Otherwise `false` and the caller should generate arbitrary
    /// imports.
    fn arbitrary_imports_from_available(&mut self, u: &mut Unstructured) -> Result<bool> {
        let example_module = if let Some(wasm) = self.config.available_imports.take() {
            wasm
        } else {
            return Ok(false);
        };

        #[cfg(feature = "wasmparser")]
        {
            self._arbitrary_imports_from_available(u, &example_module)?;
            Ok(true)
        }
        #[cfg(not(feature = "wasmparser"))]
        {
            let _ = (example_module, u);
            panic!("support for `available_imports` was disabled at compile time");
        }
    }

    #[cfg(feature = "wasmparser")]
    fn _arbitrary_imports_from_available(
        &mut self,
        u: &mut Unstructured,
        example_module: &[u8],
    ) -> Result<()> {
        // First, parse the module-by-example to collect the types and imports.
        //
        // `available_types` will map from a signature index (which is the same as the index into
        // this vector) as it appears in the parsed code, to the type itself as well as to the
        // index in our newly generated module. Initially the option is `None` and will become a
        // `Some` when we encounter an import that uses this signature in the next portion of this
        // function. See also the `make_func_type` closure below.
        let mut available_types = Vec::new();
        let mut available_imports = Vec::<wasmparser::Import>::new();
        for payload in wasmparser::Parser::new(0).parse_all(&example_module) {
            match payload.expect("could not parse the available import payload") {
                wasmparser::Payload::TypeSection(type_reader) => {
                    for ty in type_reader.into_iter_err_on_gc_types() {
                        let ty = ty.expect("could not parse type section");
                        available_types.push((ty, None));
                    }
                }
                wasmparser::Payload::ImportSection(import_reader) => {
                    for im in import_reader {
                        let im = im.expect("could not read import");
                        // We can immediately filter whether this is an import we want to
                        // use.
                        let use_import = u.arbitrary().unwrap_or(false);
                        if !use_import {
                            continue;
                        }
                        available_imports.push(im);
                    }
                }
                _ => {}
            }
        }

        // In this function we need to place imported function/tag types in the types section and
        // generate import entries (which refer to said types) at the same time.
        let max_types = self.config.max_types;
        let multi_value_enabled = self.config.multi_value_enabled;
        let mut new_imports = Vec::with_capacity(available_imports.len());
        let first_type_index = self.types.len();
        let mut new_types = Vec::<SubType>::new();

        // Returns the index to the translated type in the to-be type section, and the reference to
        // the type itself.
        let mut make_func_type = |parsed_sig_idx: u32| {
            let serialized_sig_idx = match available_types.get_mut(parsed_sig_idx as usize) {
                None => panic!("signature index refers to a type out of bounds"),
                Some((_, Some(idx))) => *idx as usize,
                Some((func_type, index_store)) => {
                    let multi_value_required = func_type.results().len() > 1;
                    let new_index = first_type_index + new_types.len();
                    if new_index >= max_types || (multi_value_required && !multi_value_enabled) {
                        return None;
                    }
                    let func_type = Rc::new(FuncType {
                        params: func_type
                            .params()
                            .iter()
                            .map(|t| (*t).try_into().unwrap())
                            .collect(),
                        results: func_type
                            .results()
                            .iter()
                            .map(|t| (*t).try_into().unwrap())
                            .collect(),
                    });
                    index_store.replace(new_index as u32);
                    new_types.push(SubType {
                        is_final: true,
                        supertype: None,
                        composite_type: CompositeType::Func(Rc::clone(&func_type)),
                    });
                    new_index
                }
            };
            match &new_types[serialized_sig_idx - first_type_index].composite_type {
                CompositeType::Func(f) => Some((serialized_sig_idx as u32, Rc::clone(f))),
                _ => unimplemented!(),
            }
        };

        for import in available_imports {
            let type_size_budget = self.config.max_type_size - self.type_size;
            let entity_type = match &import.ty {
                wasmparser::TypeRef::Func(sig_idx) => {
                    if self.funcs.len() >= self.config.max_funcs {
                        continue;
                    } else if let Some((sig_idx, func_type)) = make_func_type(*sig_idx) {
                        let entity = EntityType::Func(sig_idx as u32, Rc::clone(&func_type));
                        if type_size_budget < entity.size() {
                            continue;
                        }
                        self.funcs.push((sig_idx, func_type));
                        entity
                    } else {
                        continue;
                    }
                }

                wasmparser::TypeRef::Tag(wasmparser::TagType { func_type_idx, .. }) => {
                    let can_add_tag = self.tags.len() < self.config.max_tags;
                    if !self.config.exceptions_enabled || !can_add_tag {
                        continue;
                    } else if let Some((sig_idx, func_type)) = make_func_type(*func_type_idx) {
                        let tag_type = TagType {
                            func_type_idx: sig_idx,
                            func_type,
                        };
                        let entity = EntityType::Tag(tag_type.clone());
                        if type_size_budget < entity.size() {
                            continue;
                        }
                        self.tags.push(tag_type);
                        entity
                    } else {
                        continue;
                    }
                }

                wasmparser::TypeRef::Table(table_ty) => {
                    let table_ty = TableType::try_from(*table_ty).unwrap();
                    let entity = EntityType::Table(table_ty);
                    let type_size = entity.size();
                    if type_size_budget < type_size || !self.can_add_local_or_import_table() {
                        continue;
                    }
                    self.type_size += type_size;
                    self.tables.push(table_ty);
                    entity
                }

                wasmparser::TypeRef::Memory(memory_ty) => {
                    let memory_ty = MemoryType::try_from(*memory_ty).unwrap();
                    let entity = EntityType::Memory(memory_ty);
                    let type_size = entity.size();
                    if type_size_budget < type_size || !self.can_add_local_or_import_memory() {
                        continue;
                    }
                    self.type_size += type_size;
                    self.memories.push(memory_ty);
                    entity
                }

                wasmparser::TypeRef::Global(global_ty) => {
                    let global_ty = (*global_ty).try_into().unwrap();
                    let entity = EntityType::Global(global_ty);
                    let type_size = entity.size();
                    if type_size_budget < type_size || !self.can_add_local_or_import_global() {
                        continue;
                    }
                    self.type_size += type_size;
                    self.globals.push(global_ty);
                    entity
                }
            };
            new_imports.push(Import {
                module: import.module.to_string(),
                field: import.name.to_string(),
                entity_type,
            });
            self.num_imports += 1;
        }

        // Finally, add the entities we just generated.
        for ty in new_types {
            self.rec_groups.push(self.types.len()..self.types.len() + 1);
            self.add_type(ty);
        }
        self.imports.extend(new_imports);

        Ok(())
    }

    fn type_of(&self, kind: ExportKind, index: u32) -> EntityType {
        match kind {
            ExportKind::Global => EntityType::Global(self.globals[index as usize]),
            ExportKind::Memory => EntityType::Memory(self.memories[index as usize]),
            ExportKind::Table => EntityType::Table(self.tables[index as usize]),
            ExportKind::Func => {
                let (_idx, ty) = &self.funcs[index as usize];
                EntityType::Func(u32::max_value(), ty.clone())
            }
            ExportKind::Tag => EntityType::Tag(self.tags[index as usize].clone()),
        }
    }

    fn ty(&self, idx: u32) -> &SubType {
        &self.types[idx as usize]
    }

    fn func_types(&self) -> impl Iterator<Item = (u32, &FuncType)> + '_ {
        self.func_types
            .iter()
            .copied()
            .map(move |type_i| (type_i, &**self.func_type(type_i)))
    }

    fn func_type(&self, idx: u32) -> &Rc<FuncType> {
        match &self.ty(idx).composite_type {
            CompositeType::Func(f) => f,
            _ => panic!("types[{idx}] is not a func type"),
        }
    }

    fn tags(&self) -> impl Iterator<Item = (u32, &TagType)> + '_ {
        self.tags
            .iter()
            .enumerate()
            .map(move |(i, ty)| (i as u32, ty))
    }

    fn funcs(&self) -> impl Iterator<Item = (u32, &Rc<FuncType>)> + '_ {
        self.funcs
            .iter()
            .enumerate()
            .map(move |(i, (_, ty))| (i as u32, ty))
    }

    fn has_tag_func_types(&self) -> bool {
        self.tag_func_types().next().is_some()
    }

    fn tag_func_types(&self) -> impl Iterator<Item = u32> + '_ {
        self.func_types
            .iter()
            .copied()
            .filter(move |i| self.func_type(*i).results.is_empty())
    }

    fn arbitrary_valtype(&self, u: &mut Unstructured) -> Result<ValType> {
        #[derive(Arbitrary)]
        enum ValTypeClass {
            I32,
            I64,
            F32,
            F64,
            V128,
            Ref,
        }

        match u.arbitrary::<ValTypeClass>()? {
            ValTypeClass::I32 => Ok(ValType::I32),
            ValTypeClass::I64 => Ok(ValType::I64),
            ValTypeClass::F32 => Ok(ValType::F32),
            ValTypeClass::F64 => Ok(ValType::F64),
            ValTypeClass::V128 => {
                if self.config.simd_enabled {
                    Ok(ValType::V128)
                } else {
                    Ok(ValType::I32)
                }
            }
            ValTypeClass::Ref => {
                if self.config.reference_types_enabled {
                    Ok(ValType::Ref(self.arbitrary_ref_type(u)?))
                } else {
                    Ok(ValType::I32)
                }
            }
        }
    }

    fn arbitrary_global_type(&self, u: &mut Unstructured) -> Result<GlobalType> {
        Ok(GlobalType {
            val_type: self.arbitrary_valtype(u)?,
            mutable: u.arbitrary()?,
            shared: false,
        })
    }

    fn arbitrary_tag_type(&self, u: &mut Unstructured) -> Result<TagType> {
        let candidate_func_types: Vec<_> = self.tag_func_types().collect();
        arbitrary_tag_type(u, &candidate_func_types, |ty_idx| {
            self.func_type(ty_idx).clone()
        })
    }

    fn arbitrary_tags(&mut self, u: &mut Unstructured) -> Result<()> {
        if !self.config.exceptions_enabled || !self.has_tag_func_types() {
            return Ok(());
        }

        arbitrary_loop(u, self.config.min_tags, self.config.max_tags, |u| {
            if !self.can_add_local_or_import_tag() {
                return Ok(false);
            }
            self.tags.push(self.arbitrary_tag_type(u)?);
            self.num_defined_tags += 1;
            Ok(true)
        })
    }

    fn arbitrary_funcs(&mut self, u: &mut Unstructured) -> Result<()> {
        if self.func_types.is_empty() {
            return Ok(());
        }

        arbitrary_loop(u, self.config.min_funcs, self.config.max_funcs, |u| {
            if !self.can_add_local_or_import_func() {
                return Ok(false);
            }
            let max = self.func_types.len() - 1;
            let ty = self.func_types[u.int_in_range(0..=max)?];
            self.funcs.push((ty, self.func_type(ty).clone()));
            self.num_defined_funcs += 1;
            Ok(true)
        })
    }

    fn arbitrary_tables(&mut self, u: &mut Unstructured) -> Result<()> {
        arbitrary_loop(
            u,
            self.config.min_tables as usize,
            self.config.max_tables as usize,
            |u| {
                if !self.can_add_local_or_import_table() {
                    return Ok(false);
                }
                let ty = arbitrary_table_type(u, self.config(), Some(self))?;
                let init = self.arbitrary_table_init(u, ty.element_type)?;
                self.defined_tables.push(init);
                self.tables.push(ty);
                Ok(true)
            },
        )
    }

    /// Generates an arbitrary table initialization expression for a table whose
    /// element type is `ty`.
    ///
    /// Table initialization expressions were added by the GC proposal to
    /// initialize non-nullable tables.
    fn arbitrary_table_init(
        &mut self,
        u: &mut Unstructured,
        ty: RefType,
    ) -> Result<Option<ConstExpr>> {
        if !self.config.gc_enabled {
            assert!(ty.nullable);
            return Ok(None);
        }
        // Even with the GC proposal an initialization expression is not
        // required if the element type is nullable.
        if ty.nullable && u.arbitrary()? {
            return Ok(None);
        }
        let expr = self.arbitrary_const_expr(ValType::Ref(ty), u)?;
        Ok(Some(expr))
    }

    fn arbitrary_memories(&mut self, u: &mut Unstructured) -> Result<()> {
        arbitrary_loop(
            u,
            self.config.min_memories as usize,
            self.config.max_memories as usize,
            |u| {
                if !self.can_add_local_or_import_memory() {
                    return Ok(false);
                }
                self.num_defined_memories += 1;
                self.memories.push(arbitrary_memtype(u, self.config())?);
                Ok(true)
            },
        )
    }

    /// Add a new global of the given type and return its global index.
    fn add_arbitrary_global_of_type(
        &mut self,
        ty: GlobalType,
        u: &mut Unstructured,
    ) -> Result<u32> {
        let expr = self.arbitrary_const_expr(ty.val_type, u)?;
        let global_idx = self.globals.len() as u32;
        self.globals.push(ty);
        self.defined_globals.push((global_idx, expr));
        Ok(global_idx)
    }

    /// Generates an arbitrary constant expression of the type `ty`.
    fn arbitrary_const_expr(&mut self, ty: ValType, u: &mut Unstructured) -> Result<ConstExpr> {
        let mut choices = mem::take(&mut self.const_expr_choices);
        choices.clear();
        let num_funcs = self.funcs.len() as u32;

        // MVP wasm can `global.get` any immutable imported global in a
        // constant expression, and the GC proposal enables this for all
        // globals, so make all matching globals a candidate.
        for i in self.globals_for_const_expr(ty) {
            choices.push(Box::new(move |_, _| Ok(ConstExpr::global_get(i))));
        }

        // Another option for all types is to have an actual value of each type.
        // Change `ty` to any valid subtype of `ty` and then generate a matching
        // type of that value.
        let ty = self.arbitrary_matching_val_type(u, ty)?;
        match ty {
            ValType::I32 => choices.push(Box::new(|u, _| Ok(ConstExpr::i32_const(u.arbitrary()?)))),
            ValType::I64 => choices.push(Box::new(|u, _| Ok(ConstExpr::i64_const(u.arbitrary()?)))),
            ValType::F32 => choices.push(Box::new(|u, _| Ok(ConstExpr::f32_const(u.arbitrary()?)))),
            ValType::F64 => choices.push(Box::new(|u, _| Ok(ConstExpr::f64_const(u.arbitrary()?)))),
            ValType::V128 => {
                choices.push(Box::new(|u, _| Ok(ConstExpr::v128_const(u.arbitrary()?))))
            }

            ValType::Ref(ty) => {
                if ty.nullable {
                    choices.push(Box::new(move |_, _| Ok(ConstExpr::ref_null(ty.heap_type))));
                }

                match ty.heap_type {
                    HeapType::Func if num_funcs > 0 => {
                        choices.push(Box::new(move |u, _| {
                            let func = u.int_in_range(0..=num_funcs - 1)?;
                            Ok(ConstExpr::ref_func(func))
                        }));
                    }

                    HeapType::Concrete(ty) => {
                        for (i, fty) in self.funcs.iter().map(|(t, _)| *t).enumerate() {
                            if ty != fty {
                                continue;
                            }
                            choices.push(Box::new(move |_, _| Ok(ConstExpr::ref_func(i as u32))));
                        }
                    }

                    // TODO: fill out more GC types e.g `array.new` and
                    // `struct.new`
                    _ => {}
                }
            }
        }

        let f = u.choose(&choices)?;
        let ret = f(u, ty);
        self.const_expr_choices = choices;
        ret
    }

    fn arbitrary_globals(&mut self, u: &mut Unstructured) -> Result<()> {
        arbitrary_loop(u, self.config.min_globals, self.config.max_globals, |u| {
            if !self.can_add_local_or_import_global() {
                return Ok(false);
            }

            let ty = self.arbitrary_global_type(u)?;
            self.add_arbitrary_global_of_type(ty, u)?;

            Ok(true)
        })
    }

    fn required_exports(&mut self, u: &mut Unstructured) -> Result<bool> {
        let example_module = if let Some(wasm) = self.config.exports.clone() {
            wasm
        } else {
            return Ok(false);
        };

        #[cfg(feature = "wasmparser")]
        {
            self._required_exports(u, &example_module)?;
            Ok(true)
        }
        #[cfg(not(feature = "wasmparser"))]
        {
            let _ = (example_module, u);
            panic!("support for `exports` was disabled at compile time");
        }
    }

    #[cfg(feature = "wasmparser")]
    fn _required_exports(&mut self, u: &mut Unstructured, example_module: &[u8]) -> Result<()> {
        fn convert_heap_type(ty: &wasmparser::HeapType) -> HeapType {
            match ty {
                wasmparser::HeapType::Concrete(_) => {
                    panic!("Unable to handle concrete types in exports")
                }
                wasmparser::HeapType::Func => HeapType::Func,
                wasmparser::HeapType::Extern => HeapType::Extern,
                wasmparser::HeapType::Any => HeapType::Any,
                wasmparser::HeapType::None => HeapType::None,
                wasmparser::HeapType::NoExtern => HeapType::NoExtern,
                wasmparser::HeapType::NoFunc => HeapType::NoFunc,
                wasmparser::HeapType::Eq => HeapType::Eq,
                wasmparser::HeapType::Struct => HeapType::Struct,
                wasmparser::HeapType::Array => HeapType::Array,
                wasmparser::HeapType::I31 => HeapType::I31,
                wasmparser::HeapType::Exn => HeapType::Exn,
                wasmparser::HeapType::NoExn => HeapType::NoExn,
            }
        }

        fn convert_val_type(ty: &wasmparser::ValType) -> ValType {
            match ty {
                wasmparser::ValType::I32 => ValType::I32,
                wasmparser::ValType::I64 => ValType::I64,
                wasmparser::ValType::F32 => ValType::F32,
                wasmparser::ValType::F64 => ValType::F64,
                wasmparser::ValType::V128 => ValType::V128,
                wasmparser::ValType::Ref(r) => ValType::Ref(RefType {
                    nullable: r.is_nullable(),
                    heap_type: convert_heap_type(&r.heap_type()),
                }),
            }
        }

        fn convert_export_kind(kind: &wasmparser::ExternalKind) -> ExportKind {
            match kind {
                wasmparser::ExternalKind::Func => ExportKind::Func,
                wasmparser::ExternalKind::Table => ExportKind::Table,
                wasmparser::ExternalKind::Memory => ExportKind::Memory,
                wasmparser::ExternalKind::Global => ExportKind::Global,
                wasmparser::ExternalKind::Tag => ExportKind::Tag,
            }
        }

        let mut required_exports: Vec<wasmparser::Export> = vec![];
        let mut validator = wasmparser::Validator::new();
        let exports_types = validator
            .validate_all(&example_module)
            .expect("Failed to validate `exports` Wasm");
        for payload in wasmparser::Parser::new(0).parse_all(&example_module) {
            match payload.expect("Failed to read `exports` Wasm") {
                wasmparser::Payload::ExportSection(export_reader) => {
                    required_exports = export_reader
                        .into_iter()
                        .collect::<Result<_, _>>()
                        .expect("Failed to read `exports` export section");
                }
                _ => {}
            }
        }

        // For each export, add necessary prerequisites to the module.
        for export in required_exports {
            let new_index = match exports_types
                .entity_type_from_export(&export)
                .unwrap_or_else(|| {
                    panic!(
                        "Unable to get type from export {:?} in `exports` Wasm",
                        export,
                    )
                }) {
                // For functions, add the type and a function with that type.
                wasmparser::types::EntityType::Func(id) => {
                    let subtype = exports_types.get(id).unwrap_or_else(|| {
                        panic!(
                            "Unable to get subtype for function {:?} in `exports` Wasm",
                            id
                        )
                    });
                    match &subtype.composite_type {
                        wasmparser::CompositeType::Func(func_type) => {
                            assert!(
                                subtype.is_final,
                                "Subtype {:?} from `exports` Wasm is not final",
                                subtype
                            );
                            assert!(
                                subtype.supertype_idx.is_none(),
                                "Subtype {:?} from `exports` Wasm has non-empty supertype",
                                subtype
                            );
                            let new_type = Rc::new(FuncType {
                                params: func_type
                                    .params()
                                    .into_iter()
                                    .map(convert_val_type)
                                    .collect(),
                                results: func_type
                                    .results()
                                    .into_iter()
                                    .map(convert_val_type)
                                    .collect(),
                            });
                            self.rec_groups.push(self.types.len()..self.types.len() + 1);
                            let type_index = self.add_type(SubType {
                                is_final: true,
                                supertype: None,
                                composite_type: CompositeType::Func(Rc::clone(&new_type)),
                            });
                            let func_index = self.funcs.len() as u32;
                            self.funcs.push((type_index, new_type));
                            self.num_defined_funcs += 1;
                            func_index
                        }
                        _ => panic!(
                            "Unable to handle type {:?} from `exports` Wasm",
                            subtype.composite_type
                        ),
                    }
                }
                // For globals, add a new global.
                wasmparser::types::EntityType::Global(global_type) => self
                    .add_arbitrary_global_of_type(
                        GlobalType {
                            val_type: convert_val_type(&global_type.content_type),
                            mutable: global_type.mutable,
                            shared: global_type.shared,
                        },
                        u,
                    )?,
                wasmparser::types::EntityType::Table(_)
                | wasmparser::types::EntityType::Memory(_)
                | wasmparser::types::EntityType::Tag(_) => {
                    panic!(
                        "Config `exports` has an export of type {:?} which cannot yet be handled.",
                        export.kind
                    )
                }
            };
            self.exports.push((
                export.name.to_string(),
                convert_export_kind(&export.kind),
                new_index,
            ));
            self.export_names.insert(export.name.to_string());
        }

        Ok(())
    }

    fn arbitrary_exports(&mut self, u: &mut Unstructured) -> Result<()> {
        if self.config.max_type_size < self.type_size && !self.config.export_everything {
            return Ok(());
        }

        // Build up a list of candidates for each class of import
        let mut choices: Vec<Vec<(ExportKind, u32)>> = Vec::with_capacity(6);
        choices.push(
            (0..self.funcs.len())
                .map(|i| (ExportKind::Func, i as u32))
                .collect(),
        );
        choices.push(
            (0..self.tables.len())
                .map(|i| (ExportKind::Table, i as u32))
                .collect(),
        );
        choices.push(
            (0..self.memories.len())
                .map(|i| (ExportKind::Memory, i as u32))
                .collect(),
        );
        choices.push(
            (0..self.globals.len())
                .map(|i| (ExportKind::Global, i as u32))
                .collect(),
        );

        // If the configuration demands exporting everything, we do so here and
        // early-return.
        if self.config.export_everything {
            for choices_by_kind in choices {
                for (kind, idx) in choices_by_kind {
                    let name = unique_string(1_000, &mut self.export_names, u)?;
                    self.add_arbitrary_export(name, kind, idx)?;
                }
            }
            return Ok(());
        }

        arbitrary_loop(u, self.config.min_exports, self.config.max_exports, |u| {
            // Remove all candidates for export whose type size exceeds our
            // remaining budget for type size. Then also remove any classes
            // of exports which no longer have any candidates.
            //
            // If there's nothing remaining after this, then we're done.
            let max_size = self.config.max_type_size - self.type_size;
            for list in choices.iter_mut() {
                list.retain(|(kind, idx)| self.type_of(*kind, *idx).size() + 1 < max_size);
            }
            choices.retain(|list| !list.is_empty());
            if choices.is_empty() {
                return Ok(false);
            }

            // Pick a name, then pick the export, and then we can record
            // information about the chosen export.
            let name = unique_string(1_000, &mut self.export_names, u)?;
            let list = u.choose(&choices)?;
            let (kind, idx) = *u.choose(list)?;
            self.add_arbitrary_export(name, kind, idx)?;
            Ok(true)
        })
    }

    fn add_arbitrary_export(&mut self, name: String, kind: ExportKind, idx: u32) -> Result<()> {
        let ty = self.type_of(kind, idx);
        self.type_size += 1 + ty.size();
        if self.type_size <= self.config.max_type_size {
            self.exports.push((name, kind, idx));
            Ok(())
        } else {
            // If our addition of exports takes us above the allowed number of
            // types, we fail; this error code is not the most illustrative of
            // the cause but is the best available from `arbitrary`.
            Err(arbitrary::Error::IncorrectFormat)
        }
    }

    fn arbitrary_start(&mut self, u: &mut Unstructured) -> Result<()> {
        if !self.config.allow_start_export {
            return Ok(());
        }

        let mut choices = Vec::with_capacity(self.funcs.len() as usize);

        for (func_idx, ty) in self.funcs() {
            if ty.params.is_empty() && ty.results.is_empty() {
                choices.push(func_idx);
            }
        }

        if !choices.is_empty() && u.arbitrary().unwrap_or(false) {
            let f = *u.choose(&choices)?;
            self.start = Some(f);
        }

        Ok(())
    }

    fn arbitrary_elems(&mut self, u: &mut Unstructured) -> Result<()> {
        // Create a helper closure to choose an arbitrary offset.
        let mut global_i32 = vec![];
        let mut global_i64 = vec![];
        if !self.config.disallow_traps {
            for i in self.globals_for_const_expr(ValType::I32) {
                global_i32.push(i);
            }
            for i in self.globals_for_const_expr(ValType::I64) {
                global_i64.push(i);
            }
        }
        let disallow_traps = self.config.disallow_traps;
        let arbitrary_active_elem =
            |u: &mut Unstructured, min_mem_size: u64, table: Option<u32>, table_ty: &TableType| {
                let global_choices = if table_ty.table64 {
                    &global_i64
                } else {
                    &global_i32
                };
                let (offset, max_size_hint) = if !global_choices.is_empty() && u.arbitrary()? {
                    let g = u.choose(&global_choices)?;
                    (Offset::Global(*g), None)
                } else {
                    let max_mem_size = if disallow_traps {
                        table_ty.minimum
                    } else if table_ty.table64 {
                        u64::MAX
                    } else {
                        u64::from(u32::MAX)
                    };
                    let offset = arbitrary_offset(u, min_mem_size, max_mem_size, 0)?;
                    let max_size_hint = if disallow_traps
                        || (offset <= min_mem_size
                            && u.int_in_range(0..=CHANCE_OFFSET_INBOUNDS)? != 0)
                    {
                        Some(min_mem_size - offset)
                    } else {
                        None
                    };

                    let offset = if table_ty.table64 {
                        Offset::Const64(offset as i64)
                    } else {
                        Offset::Const32(offset as i32)
                    };
                    (offset, max_size_hint)
                };
                Ok((ElementKind::Active { table, offset }, max_size_hint))
            };

        // Generate a list of candidates for "kinds" of elements segments. For
        // example we can have an active segment for any existing table or
        // passive/declared segments if the right wasm features are enabled.
        type GenElemSegment<'a> =
            dyn Fn(&mut Unstructured) -> Result<(ElementKind, Option<u64>)> + 'a;
        let mut choices: Vec<Box<GenElemSegment>> = Vec::new();

        // Bulk memory enables passive/declared segments, and note that the
        // types used are selected later.
        if self.config.bulk_memory_enabled {
            choices.push(Box::new(|_| Ok((ElementKind::Passive, None))));
            choices.push(Box::new(|_| Ok((ElementKind::Declared, None))));
        }

        for (i, ty) in self.tables.iter().enumerate() {
            // If this table starts with no capacity then any non-empty element
            // segment placed onto it will immediately trap, which isn't too
            // too interesting. If that's the case give it an unlikely chance
            // of proceeding.
            if ty.minimum == 0 && u.int_in_range(0..=CHANCE_SEGMENT_ON_EMPTY)? != 0 {
                continue;
            }

            let minimum = ty.minimum;
            // If the first table is a funcref table then it's a candidate for
            // the MVP encoding of element segments.
            let ty = *ty;
            if i == 0 && ty.element_type == RefType::FUNCREF {
                choices.push(Box::new(move |u| {
                    arbitrary_active_elem(u, minimum, None, &ty)
                }));
            }
            if self.config.bulk_memory_enabled {
                let idx = Some(i as u32);
                choices.push(Box::new(move |u| {
                    arbitrary_active_elem(u, minimum, idx, &ty)
                }));
            }
        }

        if choices.is_empty() {
            return Ok(());
        }

        arbitrary_loop(
            u,
            self.config.min_element_segments,
            self.config.max_element_segments,
            |u| {
                // Pick a kind of element segment to generate which will also
                // give us a hint of the maximum size, if any.
                let (kind, max_size_hint) = u.choose(&choices)?(u)?;
                let max = max_size_hint
                    .map(|i| usize::try_from(i).unwrap())
                    .unwrap_or_else(|| self.config.max_elements);

                // Infer, from the kind of segment, the type of the element
                // segment. Passive/declared segments can be declared with any
                // reference type, but active segments must match their table.
                let ty = match kind {
                    ElementKind::Passive | ElementKind::Declared => self.arbitrary_ref_type(u)?,
                    ElementKind::Active { table, .. } => {
                        let idx = table.unwrap_or(0);
                        self.arbitrary_matching_ref_type(u, self.tables[idx as usize].element_type)?
                    }
                };

                // The `Elements::Functions` encoding is only possible when the
                // element type is a `funcref` because the binary format can't
                // allow encoding any other type in that form.
                let can_use_function_list = ty == RefType::FUNCREF;
                if !self.config.reference_types_enabled {
                    assert!(can_use_function_list);
                }

                // If a function list is possible then build up a list of
                // functions that can be selected from.
                let mut func_candidates = Vec::new();
                if can_use_function_list {
                    match ty.heap_type {
                        HeapType::Func => {
                            func_candidates.extend(0..self.funcs.len() as u32);
                        }
                        HeapType::Concrete(ty) => {
                            for (i, (fty, _)) in self.funcs.iter().enumerate() {
                                if *fty == ty {
                                    func_candidates.push(i as u32);
                                }
                            }
                        }
                        _ => {}
                    }
                }

                // And finally actually generate the arbitrary elements of this
                // element segment. Function indices are used if they're either
                // forced or allowed, and otherwise expressions are used
                // instead.
                let items = if !self.config.reference_types_enabled
                    || (can_use_function_list && u.arbitrary()?)
                {
                    let mut init = vec![];
                    if func_candidates.len() > 0 {
                        arbitrary_loop(u, self.config.min_elements, max, |u| {
                            let func_idx = *u.choose(&func_candidates)?;
                            init.push(func_idx);
                            Ok(true)
                        })?;
                    }
                    Elements::Functions(init)
                } else {
                    let mut init = vec![];
                    arbitrary_loop(u, self.config.min_elements, max, |u| {
                        init.push(self.arbitrary_const_expr(ValType::Ref(ty), u)?);
                        Ok(true)
                    })?;
                    Elements::Expressions(init)
                };

                self.elems.push(ElementSegment { kind, ty, items });
                Ok(true)
            },
        )
    }

    fn arbitrary_code(&mut self, u: &mut Unstructured) -> Result<()> {
        self.compute_interesting_values();

        self.code.reserve(self.num_defined_funcs);
        let mut allocs = CodeBuilderAllocations::new(self, self.config.exports.is_some());
        for (_, ty) in self.funcs[self.funcs.len() - self.num_defined_funcs..].iter() {
            let body = self.arbitrary_func_body(u, ty, &mut allocs)?;
            self.code.push(body);
        }
        allocs.finish(u, self)?;
        Ok(())
    }

    fn arbitrary_func_body(
        &self,
        u: &mut Unstructured,
        ty: &FuncType,
        allocs: &mut CodeBuilderAllocations,
    ) -> Result<Code> {
        let mut locals = self.arbitrary_locals(u)?;
        let builder = allocs.builder(ty, &mut locals);
        let instructions = if self.config.allow_invalid_funcs && u.arbitrary().unwrap_or(false) {
            Instructions::Arbitrary(arbitrary_vec_u8(u)?)
        } else {
            Instructions::Generated(builder.arbitrary(u, self)?)
        };

        Ok(Code {
            locals,
            instructions,
        })
    }

    fn arbitrary_locals(&self, u: &mut Unstructured) -> Result<Vec<ValType>> {
        let mut ret = Vec::new();
        arbitrary_loop(u, 0, 100, |u| {
            ret.push(self.arbitrary_valtype(u)?);
            Ok(true)
        })?;
        Ok(ret)
    }

    fn arbitrary_data(&mut self, u: &mut Unstructured) -> Result<()> {
        // With bulk-memory we can generate passive data, otherwise if there are
        // no memories we can't generate any data.
        let memories = self.memories.len() as u32;
        if memories == 0 && !self.config.bulk_memory_enabled {
            return Ok(());
        }
        let disallow_traps = self.config.disallow_traps;
        let mut choices32: Vec<Box<dyn Fn(&mut Unstructured, u64, usize) -> Result<Offset>>> =
            vec![];
        choices32.push(Box::new(|u, min_size, data_len| {
            let min = u32::try_from(min_size.saturating_mul(64 * 1024))
                .unwrap_or(u32::MAX)
                .into();
            let max = if disallow_traps { min } else { u32::MAX.into() };
            Ok(Offset::Const32(
                arbitrary_offset(u, min, max, data_len)? as i32
            ))
        }));
        let mut choices64: Vec<Box<dyn Fn(&mut Unstructured, u64, usize) -> Result<Offset>>> =
            vec![];
        choices64.push(Box::new(|u, min_size, data_len| {
            let min = min_size.saturating_mul(64 * 1024);
            let max = if disallow_traps { min } else { u64::MAX };
            Ok(Offset::Const64(
                arbitrary_offset(u, min, max, data_len)? as i64
            ))
        }));
        if !self.config.disallow_traps {
            for i in self.globals_for_const_expr(ValType::I32) {
                choices32.push(Box::new(move |_, _, _| Ok(Offset::Global(i))));
            }
            for i in self.globals_for_const_expr(ValType::I64) {
                choices64.push(Box::new(move |_, _, _| Ok(Offset::Global(i))));
            }
        }

        // Build a list of candidate memories that we'll add data initializers
        // for. If a memory doesn't have an initial size then any initializers
        // for that memory will trap instantiation, which isn't too
        // interesting. Try to make this happen less often by making it less
        // likely that a memory with 0 size will have a data segment.
        let mut memories = Vec::new();
        for (i, mem) in self.memories.iter().enumerate() {
            if mem.minimum > 0 || u.int_in_range(0..=CHANCE_SEGMENT_ON_EMPTY)? == 0 {
                memories.push(i as u32);
            }
        }

        // With memories we can generate data segments, and with bulk memory we
        // can generate passive segments. Without these though we can't create
        // a valid module with data segments.
        if memories.is_empty() && !self.config.bulk_memory_enabled {
            return Ok(());
        }

        arbitrary_loop(
            u,
            self.config.min_data_segments,
            self.config.max_data_segments,
            |u| {
                let mut init: Vec<u8> = u.arbitrary()?;

                // Passive data can only be generated if bulk memory is enabled.
                // Otherwise if there are no memories we *only* generate passive
                // data. Finally if all conditions are met we use an input byte to
                // determine if it should be passive or active.
                let kind =
                    if self.config.bulk_memory_enabled && (memories.is_empty() || u.arbitrary()?) {
                        DataSegmentKind::Passive
                    } else {
                        let memory_index = *u.choose(&memories)?;
                        let mem = &self.memories[memory_index as usize];
                        let f = if mem.memory64 {
                            u.choose(&choices64)?
                        } else {
                            u.choose(&choices32)?
                        };
                        let mut offset = f(u, mem.minimum, init.len())?;

                        // If traps are disallowed then truncate the size of the
                        // data segment to the minimum size of memory to guarantee
                        // it will fit. Afterwards ensure that the offset of the
                        // data segment is in-bounds by clamping it to the
                        if self.config.disallow_traps {
                            let max_size = (u64::MAX / 64 / 1024).min(mem.minimum) * 64 * 1024;
                            init.truncate(max_size as usize);
                            let max_offset = max_size - init.len() as u64;
                            match &mut offset {
                                Offset::Const32(x) => {
                                    *x = (*x as u64).min(max_offset) as i32;
                                }
                                Offset::Const64(x) => {
                                    *x = (*x as u64).min(max_offset) as i64;
                                }
                                Offset::Global(_) => unreachable!(),
                            }
                        }
                        DataSegmentKind::Active {
                            offset,
                            memory_index,
                        }
                    };
                self.data.push(DataSegment { kind, init });
                Ok(true)
            },
        )
    }

    fn params_results(&self, ty: &BlockType) -> (Vec<ValType>, Vec<ValType>) {
        match ty {
            BlockType::Empty => (vec![], vec![]),
            BlockType::Result(t) => (vec![], vec![*t]),
            BlockType::FunctionType(ty) => {
                let ty = self.func_type(*ty);
                (ty.params.to_vec(), ty.results.to_vec())
            }
        }
    }

    /// Returns an iterator of all globals which can be used in constant
    /// expressions for a value of type `ty` specified.
    fn globals_for_const_expr(&self, ty: ValType) -> impl Iterator<Item = u32> + '_ {
        // Before the GC proposal only imported globals could be referenced, but
        // the GC proposal relaxed this feature to allow any global.
        let num_imported_globals = self.globals.len() - self.defined_globals.len();
        let max_global = if self.config.gc_enabled {
            self.globals.len()
        } else {
            num_imported_globals
        };

        self.globals[..max_global]
            .iter()
            .enumerate()
            .filter_map(move |(i, g)| {
                // Mutable globals cannot participate in constant expressions,
                // but otherwise so long as the global is a subtype of the
                // desired type it's a candidate.
                if !g.mutable && self.val_type_is_sub_type(g.val_type, ty) {
                    Some(i as u32)
                } else {
                    None
                }
            })
    }

    fn compute_interesting_values(&mut self) {
        debug_assert!(self.interesting_values32.is_empty());
        debug_assert!(self.interesting_values64.is_empty());

        let mut interesting_values32 = HashSet::new();
        let mut interesting_values64 = HashSet::new();

        let mut interesting = |val: u64| {
            interesting_values32.insert(val as u32);
            interesting_values64.insert(val);
        };

        // Zero is always interesting.
        interesting(0);

        // Max values are always interesting.
        interesting(u8::MAX as _);
        interesting(u16::MAX as _);
        interesting(u32::MAX as _);
        interesting(u64::MAX);

        // Min values are always interesting.
        interesting(i8::MIN as _);
        interesting(i16::MIN as _);
        interesting(i32::MIN as _);
        interesting(i64::MIN as _);

        for i in 0..64 {
            // Powers of two.
            interesting(1 << i);

            // Inverted powers of two.
            interesting(!(1 << i));

            // Powers of two minus one, AKA high bits unset and low bits set.
            interesting((1 << i) - 1);

            // Negative powers of two, AKA high bits set and low bits unset.
            interesting(((1_i64 << 63) >> i) as _);
        }

        // Some repeating bit patterns.
        for pattern in [0b01010101, 0b00010001, 0b00010001, 0b00000001] {
            for b in [pattern, !pattern] {
                interesting(u64::from_ne_bytes([b, b, b, b, b, b, b, b]));
            }
        }

        // Interesting float values.
        let mut interesting_f64 = |x: f64| interesting(x.to_bits());
        interesting_f64(0.0);
        interesting_f64(-0.0);
        interesting_f64(f64::INFINITY);
        interesting_f64(f64::NEG_INFINITY);
        interesting_f64(f64::EPSILON);
        interesting_f64(-f64::EPSILON);
        interesting_f64(f64::MIN);
        interesting_f64(f64::MIN_POSITIVE);
        interesting_f64(f64::MAX);
        interesting_f64(f64::NAN);
        let mut interesting_f32 = |x: f32| interesting(x.to_bits() as _);
        interesting_f32(0.0);
        interesting_f32(-0.0);
        interesting_f32(f32::INFINITY);
        interesting_f32(f32::NEG_INFINITY);
        interesting_f32(f32::EPSILON);
        interesting_f32(-f32::EPSILON);
        interesting_f32(f32::MIN);
        interesting_f32(f32::MIN_POSITIVE);
        interesting_f32(f32::MAX);
        interesting_f32(f32::NAN);

        // Interesting values related to table bounds.
        for t in self.tables.iter() {
            interesting(t.minimum as _);
            if let Some(x) = t.minimum.checked_add(1) {
                interesting(x as _);
            }

            if let Some(x) = t.maximum {
                interesting(x as _);
                if let Some(y) = x.checked_add(1) {
                    interesting(y as _);
                }
            }
        }

        // Interesting values related to memory bounds.
        for m in self.memories.iter() {
            let min = m.minimum.saturating_mul(crate::page_size(m).into());
            interesting(min);
            for i in 0..5 {
                if let Some(x) = min.checked_add(1 << i) {
                    interesting(x);
                }
                if let Some(x) = min.checked_sub(1 << i) {
                    interesting(x);
                }
            }

            if let Some(max) = m.maximum {
                let max = max.saturating_mul(crate::page_size(m).into());
                interesting(max);
                for i in 0..5 {
                    if let Some(x) = max.checked_add(1 << i) {
                        interesting(x);
                    }
                    if let Some(x) = max.checked_sub(1 << i) {
                        interesting(x);
                    }
                }
            }
        }

        self.interesting_values32.extend(interesting_values32);
        self.interesting_values64.extend(interesting_values64);

        // Sort for determinism.
        self.interesting_values32.sort();
        self.interesting_values64.sort();
    }

    fn arbitrary_const_instruction(
        &self,
        ty: ValType,
        u: &mut Unstructured<'_>,
    ) -> Result<Instruction> {
        debug_assert!(self.interesting_values32.len() > 0);
        debug_assert!(self.interesting_values64.len() > 0);
        match ty {
            ValType::I32 => Ok(Instruction::I32Const(if u.arbitrary()? {
                *u.choose(&self.interesting_values32)? as i32
            } else {
                u.arbitrary()?
            })),
            ValType::I64 => Ok(Instruction::I64Const(if u.arbitrary()? {
                *u.choose(&self.interesting_values64)? as i64
            } else {
                u.arbitrary()?
            })),
            ValType::F32 => Ok(Instruction::F32Const(if u.arbitrary()? {
                f32::from_bits(*u.choose(&self.interesting_values32)?)
            } else {
                u.arbitrary()?
            })),
            ValType::F64 => Ok(Instruction::F64Const(if u.arbitrary()? {
                f64::from_bits(*u.choose(&self.interesting_values64)?)
            } else {
                u.arbitrary()?
            })),
            ValType::V128 => Ok(Instruction::V128Const(if u.arbitrary()? {
                let upper = (*u.choose(&self.interesting_values64)? as i128) << 64;
                let lower = *u.choose(&self.interesting_values64)? as i128;
                upper | lower
            } else {
                u.arbitrary()?
            })),
            ValType::Ref(ty) => {
                assert!(ty.nullable);
                Ok(Instruction::RefNull(ty.heap_type))
            }
        }
    }
}

pub(crate) fn arbitrary_limits64(
    u: &mut Unstructured,
    min_minimum: Option<u64>,
    max_minimum: u64,
    max_required: bool,
    max_inbounds: u64,
) -> Result<(u64, Option<u64>)> {
    let min = gradually_grow(u, min_minimum.unwrap_or(0), max_inbounds, max_minimum)?;
    let max = if max_required || u.arbitrary().unwrap_or(false) {
        Some(u.int_in_range(min..=max_minimum)?)
    } else {
        None
    };
    Ok((min, max))
}

pub(crate) fn configured_valtypes(config: &Config) -> Vec<ValType> {
    let mut valtypes = Vec::with_capacity(25);
    valtypes.push(ValType::I32);
    valtypes.push(ValType::I64);
    valtypes.push(ValType::F32);
    valtypes.push(ValType::F64);
    if config.simd_enabled {
        valtypes.push(ValType::V128);
    }
    if config.gc_enabled {
        for nullable in [
            // TODO: For now, only create allow nullable reference
            // types. Eventually we should support non-nullable reference types,
            // but this means that we will also need to recognize when it is
            // impossible to create an instance of the reference (eg `(ref
            // nofunc)` has no instances, and self-referential types that
            // contain a non-null self-reference are also impossible to create).
            true,
        ] {
            for heap_type in [
                HeapType::Any,
                HeapType::Eq,
                HeapType::I31,
                HeapType::Array,
                HeapType::Struct,
                HeapType::None,
                HeapType::Func,
                HeapType::NoFunc,
                HeapType::Extern,
                HeapType::NoExtern,
            ] {
                valtypes.push(ValType::Ref(RefType {
                    nullable,
                    heap_type,
                }));
            }
        }
    } else if config.reference_types_enabled {
        valtypes.push(ValType::EXTERNREF);
        valtypes.push(ValType::FUNCREF);
    }
    valtypes
}

pub(crate) fn arbitrary_table_type(
    u: &mut Unstructured,
    config: &Config,
    module: Option<&Module>,
) -> Result<TableType> {
    let table64 = config.memory64_enabled && u.arbitrary()?;
    // We don't want to generate tables that are too large on average, so
    // keep the "inbounds" limit here a bit smaller.
    let max_inbounds = 10_000;
    let min_elements = if config.disallow_traps { Some(1) } else { None };
    let max_elements = min_elements.unwrap_or(0).max(config.max_table_elements);
    let (minimum, maximum) = arbitrary_limits64(
        u,
        min_elements,
        max_elements,
        config.table_max_size_required,
        max_inbounds.min(max_elements),
    )?;
    if config.disallow_traps {
        assert!(minimum > 0);
    }
    let element_type = match module {
        Some(module) => module.arbitrary_ref_type(u)?,
        None => RefType::FUNCREF,
    };
    Ok(TableType {
        element_type,
        minimum,
        maximum,
        table64,
    })
}

pub(crate) fn arbitrary_memtype(u: &mut Unstructured, config: &Config) -> Result<MemoryType> {
    // When threads are enabled, we only want to generate shared memories about
    // 25% of the time.
    let shared = config.threads_enabled && u.ratio(1, 4)?;
    // We want to favor memories <= 1gb in size, allocate at most 16k pages,
    // depending on the maximum number of memories.
    let memory64 = config.memory64_enabled && u.arbitrary()?;
    let page_size = if config.custom_page_sizes_enabled && u.arbitrary()? {
        Some(1 << u.int_in_range(0..=16)?)
    } else {
        None
    };
    let max_inbounds = 16 * 1024 / u64::try_from(config.max_memories).unwrap();
    let min_pages = if config.disallow_traps { Some(1) } else { None };
    let max_pages = min_pages.unwrap_or(0).max(if memory64 {
        config.max_memory64_pages
    } else {
        config.max_memory32_pages
    });
    let (minimum, maximum) = arbitrary_limits64(
        u,
        min_pages,
        max_pages,
        config.memory_max_size_required || shared,
        max_inbounds.min(max_pages),
    )?;
    Ok(MemoryType {
        minimum,
        maximum,
        memory64,
        shared,
        page_size_log2: page_size,
    })
}

pub(crate) fn arbitrary_tag_type(
    u: &mut Unstructured,
    candidate_func_types: &[u32],
    get_func_type: impl FnOnce(u32) -> Rc<FuncType>,
) -> Result<TagType> {
    let max = candidate_func_types.len() - 1;
    let ty = candidate_func_types[u.int_in_range(0..=max)?];
    Ok(TagType {
        func_type_idx: ty,
        func_type: get_func_type(ty),
    })
}

/// This function generates a number between `min` and `max`, favoring values
/// between `min` and `max_inbounds`.
///
/// The thinking behind this function is that it's used for things like offsets
/// and minimum sizes which, when very large, can trivially make the wasm oom or
/// abort with a trap. This isn't the most interesting thing to do so it tries
/// to favor numbers in the `min..max_inbounds` range to avoid immediate ooms.
fn gradually_grow(u: &mut Unstructured, min: u64, max_inbounds: u64, max: u64) -> Result<u64> {
    if min == max {
        return Ok(min);
    }
    let min = min as f64;
    let max = max as f64;
    let max_inbounds = max_inbounds as f64;
    let x = u.arbitrary::<u32>()?;
    let x = f64::from(x);
    let x = map_custom(
        x,
        f64::from(u32::MIN)..f64::from(u32::MAX),
        min..max_inbounds,
        min..max,
    );
    return Ok(x.round() as u64);

    /// Map a value from within the input range to the output range(s).
    ///
    /// This will first map the input range into the `0..1` input range, and
    /// then depending on the value it will either map it exponentially
    /// (favoring small values) into the `output_inbounds` range or it will map
    /// it into the `output` range.
    fn map_custom(
        value: f64,
        input: Range<f64>,
        output_inbounds: Range<f64>,
        output: Range<f64>,
    ) -> f64 {
        assert!(!value.is_nan(), "{}", value);
        assert!(value.is_finite(), "{}", value);
        assert!(input.start < input.end, "{} < {}", input.start, input.end);
        assert!(
            output.start < output.end,
            "{} < {}",
            output.start,
            output.end
        );
        assert!(value >= input.start, "{} >= {}", value, input.start);
        assert!(value <= input.end, "{} <= {}", value, input.end);
        assert!(
            output.start <= output_inbounds.start,
            "{} <= {}",
            output.start,
            output_inbounds.start
        );
        assert!(
            output_inbounds.end <= output.end,
            "{} <= {}",
            output_inbounds.end,
            output.end
        );

        let x = map_linear(value, input, 0.0..1.0);
        let result = if x < PCT_INBOUNDS {
            if output_inbounds.start == output_inbounds.end {
                output_inbounds.start
            } else {
                let unscaled = x * x * x * x * x * x;
                map_linear(unscaled, 0.0..1.0, output_inbounds)
            }
        } else {
            map_linear(x, 0.0..1.0, output.clone())
        };

        assert!(result >= output.start, "{} >= {}", result, output.start);
        assert!(result <= output.end, "{} <= {}", result, output.end);
        result
    }

    /// Map a value from within the input range linearly to the output range.
    ///
    /// For example, mapping `0.5` from the input range `0.0..1.0` to the output
    /// range `1.0..3.0` produces `2.0`.
    fn map_linear(
        value: f64,
        Range {
            start: in_low,
            end: in_high,
        }: Range<f64>,
        Range {
            start: out_low,
            end: out_high,
        }: Range<f64>,
    ) -> f64 {
        assert!(!value.is_nan(), "{}", value);
        assert!(value.is_finite(), "{}", value);
        assert!(in_low < in_high, "{} < {}", in_low, in_high);
        assert!(out_low < out_high, "{} < {}", out_low, out_high);
        assert!(value >= in_low, "{} >= {}", value, in_low);
        assert!(value <= in_high, "{} <= {}", value, in_high);

        let dividend = out_high - out_low;
        let divisor = in_high - in_low;
        let slope = dividend / divisor;
        let result = out_low + (slope * (value - in_low));

        assert!(result >= out_low, "{} >= {}", result, out_low);
        assert!(result <= out_high, "{} <= {}", result, out_high);
        result
    }
}

/// Selects a reasonable offset for an element or data segment. This favors
/// having the segment being in-bounds, but it may still generate
/// any offset.
fn arbitrary_offset(
    u: &mut Unstructured,
    limit_min: u64,
    limit_max: u64,
    segment_size: usize,
) -> Result<u64> {
    let size = u64::try_from(segment_size).unwrap();

    // If the segment is too big for the whole memory, just give it any
    // offset.
    if size > limit_min {
        u.int_in_range(0..=limit_max)
    } else {
        gradually_grow(u, 0, limit_min - size, limit_max)
    }
}

fn unique_import_strings(max_size: usize, u: &mut Unstructured) -> Result<(String, String)> {
    let module = limited_string(max_size, u)?;
    let field = limited_string(max_size, u)?;
    Ok((module, field))
}

fn arbitrary_vec_u8(u: &mut Unstructured) -> Result<Vec<u8>> {
    let size = u.arbitrary_len::<u8>()?;
    Ok(u.bytes(size)?.to_vec())
}

impl EntityType {
    fn size(&self) -> u32 {
        match self {
            EntityType::Tag(_)
            | EntityType::Global(_)
            | EntityType::Table(_)
            | EntityType::Memory(_) => 1,
            EntityType::Func(_, ty) => 1 + (ty.params.len() + ty.results.len()) as u32,
        }
    }
}

// A helper structure used when generating module/instance types to limit the
// amount of each kind of import created.
#[derive(Default, Clone, Copy, PartialEq)]
struct Entities {
    globals: usize,
    memories: usize,
    tables: usize,
    funcs: usize,
    tags: usize,
}

/// A container for the kinds of instructions that wasm-smith is allowed to
/// emit.
///
/// # Example
///
/// ```
/// # use wasm_smith::{InstructionKinds, InstructionKind};
/// let kinds = InstructionKinds::new(&[InstructionKind::Numeric, InstructionKind::Memory]);
/// assert!(kinds.contains(InstructionKind::Memory));
/// ```
#[derive(Clone, Copy, Debug, Default)]
#[cfg_attr(feature = "serde_derive", derive(serde_derive::Deserialize))]
pub struct InstructionKinds(pub(crate) FlagSet<InstructionKind>);

impl InstructionKinds {
    /// Create a new container.
    pub fn new(kinds: &[InstructionKind]) -> Self {
        Self(kinds.iter().fold(FlagSet::default(), |ks, k| ks | *k))
    }

    /// Include all [InstructionKind]s.
    pub fn all() -> Self {
        Self(FlagSet::full())
    }

    /// Include no [InstructionKind]s.
    pub fn none() -> Self {
        Self(FlagSet::default())
    }

    /// Check if the [InstructionKind] is contained in this set.
    #[inline]
    pub fn contains(&self, kind: InstructionKind) -> bool {
        self.0.contains(kind)
    }
}

flags! {
    /// Enumerate the categories of instructions defined in the [WebAssembly
    /// specification](https://webassembly.github.io/spec/core/syntax/instructions.html).
    #[allow(missing_docs)]
    #[cfg_attr(feature = "_internal_cli", derive(serde_derive::Deserialize))]
    pub enum InstructionKind: u16 {
        Numeric,
        Vector,
        Reference,
        Parametric,
        Variable,
        Table,
        Memory,
        Control,
        Aggregate,
    }
}

impl FromStr for InstructionKinds {
    type Err = String;
    fn from_str(s: &str) -> std::prelude::v1::Result<Self, Self::Err> {
        let mut kinds = vec![];
        for part in s.split(",") {
            let kind = InstructionKind::from_str(part)?;
            kinds.push(kind);
        }
        Ok(InstructionKinds::new(&kinds))
    }
}

impl FromStr for InstructionKind {
    type Err = String;
    fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "numeric" => Ok(InstructionKind::Numeric),
            "vector" => Ok(InstructionKind::Vector),
            "reference" => Ok(InstructionKind::Reference),
            "parametric" => Ok(InstructionKind::Parametric),
            "variable" => Ok(InstructionKind::Variable),
            "table" => Ok(InstructionKind::Table),
            "memory" => Ok(InstructionKind::Memory),
            "control" => Ok(InstructionKind::Control),
            _ => Err(format!("unknown instruction kind: {}", s)),
        }
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-smith-0.210.0/src/core/code_builder.rs

Source (jump to first uncovered line)
use super::{
    CompositeType, Elements, FuncType, Instruction, InstructionKind::*, InstructionKinds, Module,
    ValType,
};
use crate::{unique_string, MemoryOffsetChoices};
use arbitrary::{Result, Unstructured};
use std::collections::{BTreeMap, BTreeSet};
use std::rc::Rc;
use wasm_encoder::{
    ArrayType, BlockType, Catch, ConstExpr, ExportKind, FieldType, GlobalType, HeapType, MemArg,
    RefType, StorageType, StructType,
};
mod no_traps;

macro_rules! instructions {
    (
        $(
            ($predicate:expr, $generator_fn:ident, $instruction_kind:ident $(, $cost:tt)?),
        )*
    ) => {
        static NUM_OPTIONS: usize = instructions!(
            @count;
            $( $generator_fn )*
        );

        fn choose_instruction(
            u: &mut Unstructured<'_>,
            module: &Module,
            allowed_instructions: InstructionKinds,
            builder: &mut CodeBuilder,
        ) -> Option<
            fn(&mut Unstructured<'_>, &Module, &mut CodeBuilder, &mut Vec<Instruction>) -> Result<()>
        > {
            builder.allocs.options.clear();
            let mut cost = 0;
            // Unroll the loop that checks whether each instruction is valid in
            // the current context and, if it is valid, pushes it onto our
            // options. Unrolling this loops lets us avoid dynamic calls through
            // function pointers and, furthermore, each call site can be branch
            // predicted and even inlined. This saved us about 30% of time in
            // the `corpus` benchmark.
            $(
                let predicate: Option<fn(&Module, &mut CodeBuilder) -> bool> = $predicate;
                if predicate.map_or(true, |f| f(module, builder))
                    && allowed_instructions.contains($instruction_kind) {
                    builder.allocs.options.push(($generator_fn, cost));
                    cost += 1000 $(- $cost)?;
                }
            )*

            // If there aren't actually any candidate instructions due to
            // various filters in place then return `None` to indicate the
            // situation.
            if cost == 0 {
                return None;
            }

            let i = u.int_in_range(0..=cost).ok()?;
            let idx = builder
                .allocs
                .options
                .binary_search_by_key(&i,|p| p.1)
                .unwrap_or_else(|i| i - 1);
            Some(builder.allocs.options[idx].0)
        }
    };

    ( @count; ) => {
        0
    };
    ( @count; $x:ident $( $xs:ident )* ) => {
        1 + instructions!( @count; $( $xs )* )
    };
}

// The static set of options of instruction to generate that could be valid at
// some given time. One entry per Wasm instruction.
//
// Each entry is made up of up to three parts:
//
// 1. A predicate for whether this is a valid choice, if any. `None` means that
//    the choice is always applicable.
//
// 2. The function to generate the instruction, given that we've made this
//    choice.
//
// 3. The `InstructionKind` the instruction belongs to; this allows filtering
//    out instructions by category.
//
// 4. An optional number used to weight how often this instruction is chosen.
//    Higher numbers are less likely to be chosen, and number specified must be
//    less than 1000.
instructions! {
    // Control instructions.
    (Some(unreachable_valid), unreachable, Control, 990),
    (None, nop, Control, 800),
    (None, block, Control),
    (None, r#loop, Control),
    (Some(try_table_valid), try_table, Control),
    (Some(if_valid), r#if, Control),
    (Some(else_valid), r#else, Control),
    (Some(end_valid), end, Control),
    (Some(br_valid), br, Control),
    (Some(br_if_valid), br_if, Control),
    (Some(br_table_valid), br_table, Control),
    (Some(return_valid), r#return, Control, 900),
    (Some(call_valid), call, Control),
    (Some(call_ref_valid), call_ref, Control),
    (Some(call_indirect_valid), call_indirect, Control),
    (Some(return_call_valid), return_call, Control),
    (Some(return_call_ref_valid), return_call_ref, Control),
    (Some(return_call_indirect_valid), return_call_indirect, Control),
    (Some(throw_valid), throw, Control, 850),
    (Some(throw_ref_valid), throw_ref, Control, 850),
    (Some(br_on_null_valid), br_on_null, Control),
    (Some(br_on_non_null_valid), br_on_non_null, Control),
    (Some(br_on_cast_valid), br_on_cast, Control),
    (Some(br_on_cast_fail_valid), br_on_cast_fail, Control),
    // Parametric instructions.
    (Some(drop_valid), drop, Parametric, 990),
    (Some(select_valid), select, Parametric),
    // Variable instructions.
    (Some(local_get_valid), local_get, Variable),
    (Some(local_set_valid), local_set, Variable),
    (Some(local_set_valid), local_tee, Variable),
    (Some(global_get_valid), global_get, Variable),
    (Some(global_set_valid), global_set, Variable),
    // Memory instructions.
    (Some(have_memory_and_offset), i32_load, Memory),
    (Some(have_memory_and_offset), i64_load, Memory),
    (Some(have_memory_and_offset), f32_load, Memory),
    (Some(have_memory_and_offset), f64_load, Memory),
    (Some(have_memory_and_offset), i32_load_8_s, Memory),
    (Some(have_memory_and_offset), i32_load_8_u, Memory),
    (Some(have_memory_and_offset), i32_load_16_s, Memory),
    (Some(have_memory_and_offset), i32_load_16_u, Memory),
    (Some(have_memory_and_offset), i64_load_8_s, Memory),
    (Some(have_memory_and_offset), i64_load_16_s, Memory),
    (Some(have_memory_and_offset), i64_load_32_s, Memory),
    (Some(have_memory_and_offset), i64_load_8_u, Memory),
    (Some(have_memory_and_offset), i64_load_16_u, Memory),
    (Some(have_memory_and_offset), i64_load_32_u, Memory),
    (Some(i32_store_valid), i32_store, Memory),
    (Some(i64_store_valid), i64_store, Memory),
    (Some(f32_store_valid), f32_store, Memory),
    (Some(f64_store_valid), f64_store, Memory),
    (Some(i32_store_valid), i32_store_8, Memory),
    (Some(i32_store_valid), i32_store_16, Memory),
    (Some(i64_store_valid), i64_store_8, Memory),
    (Some(i64_store_valid), i64_store_16, Memory),
    (Some(i64_store_valid), i64_store_32, Memory),
    (Some(have_memory), memory_size, Memory),
    (Some(memory_grow_valid), memory_grow, Memory),
    (Some(memory_init_valid), memory_init, Memory),
    (Some(data_drop_valid), data_drop, Memory),
    (Some(memory_copy_valid), memory_copy, Memory),
    (Some(memory_fill_valid), memory_fill, Memory),
    // Numeric instructions.
    (None, i32_const, Numeric),
    (None, i64_const, Numeric),
    (None, f32_const, Numeric),
    (None, f64_const, Numeric),
    (Some(i32_on_stack), i32_eqz, Numeric),
    (Some(i32_i32_on_stack), i32_eq, Numeric),
    (Some(i32_i32_on_stack), i32_ne, Numeric),
    (Some(i32_i32_on_stack), i32_lt_s, Numeric),
    (Some(i32_i32_on_stack), i32_lt_u, Numeric),
    (Some(i32_i32_on_stack), i32_gt_s, Numeric),
    (Some(i32_i32_on_stack), i32_gt_u, Numeric),
    (Some(i32_i32_on_stack), i32_le_s, Numeric),
    (Some(i32_i32_on_stack), i32_le_u, Numeric),
    (Some(i32_i32_on_stack), i32_ge_s, Numeric),
    (Some(i32_i32_on_stack), i32_ge_u, Numeric),
    (Some(i64_on_stack), i64_eqz, Numeric),
    (Some(i64_i64_on_stack), i64_eq, Numeric),
    (Some(i64_i64_on_stack), i64_ne, Numeric),
    (Some(i64_i64_on_stack), i64_lt_s, Numeric),
    (Some(i64_i64_on_stack), i64_lt_u, Numeric),
    (Some(i64_i64_on_stack), i64_gt_s, Numeric),
    (Some(i64_i64_on_stack), i64_gt_u, Numeric),
    (Some(i64_i64_on_stack), i64_le_s, Numeric),
    (Some(i64_i64_on_stack), i64_le_u, Numeric),
    (Some(i64_i64_on_stack), i64_ge_s, Numeric),
    (Some(i64_i64_on_stack), i64_ge_u, Numeric),
    (Some(f32_f32_on_stack), f32_eq, Numeric),
    (Some(f32_f32_on_stack), f32_ne, Numeric),
    (Some(f32_f32_on_stack), f32_lt, Numeric),
    (Some(f32_f32_on_stack), f32_gt, Numeric),
    (Some(f32_f32_on_stack), f32_le, Numeric),
    (Some(f32_f32_on_stack), f32_ge, Numeric),
    (Some(f64_f64_on_stack), f64_eq, Numeric),
    (Some(f64_f64_on_stack), f64_ne, Numeric),
    (Some(f64_f64_on_stack), f64_lt, Numeric),
    (Some(f64_f64_on_stack), f64_gt, Numeric),
    (Some(f64_f64_on_stack), f64_le, Numeric),
    (Some(f64_f64_on_stack), f64_ge, Numeric),
    (Some(i32_on_stack), i32_clz, Numeric),
    (Some(i32_on_stack), i32_ctz, Numeric),
    (Some(i32_on_stack), i32_popcnt, Numeric),
    (Some(i32_i32_on_stack), i32_add, Numeric),
    (Some(i32_i32_on_stack), i32_sub, Numeric),
    (Some(i32_i32_on_stack), i32_mul, Numeric),
    (Some(i32_i32_on_stack), i32_div_s, Numeric),
    (Some(i32_i32_on_stack), i32_div_u, Numeric),
    (Some(i32_i32_on_stack), i32_rem_s, Numeric),
    (Some(i32_i32_on_stack), i32_rem_u, Numeric),
    (Some(i32_i32_on_stack), i32_and, Numeric),
    (Some(i32_i32_on_stack), i32_or, Numeric),
    (Some(i32_i32_on_stack), i32_xor, Numeric),
    (Some(i32_i32_on_stack), i32_shl, Numeric),
    (Some(i32_i32_on_stack), i32_shr_s, Numeric),
    (Some(i32_i32_on_stack), i32_shr_u, Numeric),
    (Some(i32_i32_on_stack), i32_rotl, Numeric),
    (Some(i32_i32_on_stack), i32_rotr, Numeric),
    (Some(i64_on_stack), i64_clz, Numeric),
    (Some(i64_on_stack), i64_ctz, Numeric),
    (Some(i64_on_stack), i64_popcnt, Numeric),
    (Some(i64_i64_on_stack), i64_add, Numeric),
    (Some(i64_i64_on_stack), i64_sub, Numeric),
    (Some(i64_i64_on_stack), i64_mul, Numeric),
    (Some(i64_i64_on_stack), i64_div_s, Numeric),
    (Some(i64_i64_on_stack), i64_div_u, Numeric),
    (Some(i64_i64_on_stack), i64_rem_s, Numeric),
    (Some(i64_i64_on_stack), i64_rem_u, Numeric),
    (Some(i64_i64_on_stack), i64_and, Numeric),
    (Some(i64_i64_on_stack), i64_or, Numeric),
    (Some(i64_i64_on_stack), i64_xor, Numeric),
    (Some(i64_i64_on_stack), i64_shl, Numeric),
    (Some(i64_i64_on_stack), i64_shr_s, Numeric),
    (Some(i64_i64_on_stack), i64_shr_u, Numeric),
    (Some(i64_i64_on_stack), i64_rotl, Numeric),
    (Some(i64_i64_on_stack), i64_rotr, Numeric),
    (Some(f32_on_stack), f32_abs, Numeric),
    (Some(f32_on_stack), f32_neg, Numeric),
    (Some(f32_on_stack), f32_ceil, Numeric),
    (Some(f32_on_stack), f32_floor, Numeric),
    (Some(f32_on_stack), f32_trunc, Numeric),
    (Some(f32_on_stack), f32_nearest, Numeric),
    (Some(f32_on_stack), f32_sqrt, Numeric),
    (Some(f32_f32_on_stack), f32_add, Numeric),
    (Some(f32_f32_on_stack), f32_sub, Numeric),
    (Some(f32_f32_on_stack), f32_mul, Numeric),
    (Some(f32_f32_on_stack), f32_div, Numeric),
    (Some(f32_f32_on_stack), f32_min, Numeric),
    (Some(f32_f32_on_stack), f32_max, Numeric),
    (Some(f32_f32_on_stack), f32_copysign, Numeric),
    (Some(f64_on_stack), f64_abs, Numeric),
    (Some(f64_on_stack), f64_neg, Numeric),
    (Some(f64_on_stack), f64_ceil, Numeric),
    (Some(f64_on_stack), f64_floor, Numeric),
    (Some(f64_on_stack), f64_trunc, Numeric),
    (Some(f64_on_stack), f64_nearest, Numeric),
    (Some(f64_on_stack), f64_sqrt, Numeric),
    (Some(f64_f64_on_stack), f64_add, Numeric),
    (Some(f64_f64_on_stack), f64_sub, Numeric),
    (Some(f64_f64_on_stack), f64_mul, Numeric),
    (Some(f64_f64_on_stack), f64_div, Numeric),
    (Some(f64_f64_on_stack), f64_min, Numeric),
    (Some(f64_f64_on_stack), f64_max, Numeric),
    (Some(f64_f64_on_stack), f64_copysign, Numeric),
    (Some(i64_on_stack), i32_wrap_i64, Numeric),
    (Some(f32_on_stack), i32_trunc_f32_s, Numeric),
    (Some(f32_on_stack), i32_trunc_f32_u, Numeric),
    (Some(f64_on_stack), i32_trunc_f64_s, Numeric),
    (Some(f64_on_stack), i32_trunc_f64_u, Numeric),
    (Some(i32_on_stack), i64_extend_i32_s, Numeric),
    (Some(i32_on_stack), i64_extend_i32_u, Numeric),
    (Some(f32_on_stack), i64_trunc_f32_s, Numeric),
    (Some(f32_on_stack), i64_trunc_f32_u, Numeric),
    (Some(f64_on_stack), i64_trunc_f64_s, Numeric),
    (Some(f64_on_stack), i64_trunc_f64_u, Numeric),
    (Some(i32_on_stack), f32_convert_i32_s, Numeric),
    (Some(i32_on_stack), f32_convert_i32_u, Numeric),
    (Some(i64_on_stack), f32_convert_i64_s, Numeric),
    (Some(i64_on_stack), f32_convert_i64_u, Numeric),
    (Some(f64_on_stack), f32_demote_f64, Numeric),
    (Some(i32_on_stack), f64_convert_i32_s, Numeric),
    (Some(i32_on_stack), f64_convert_i32_u, Numeric),
    (Some(i64_on_stack), f64_convert_i64_s, Numeric),
    (Some(i64_on_stack), f64_convert_i64_u, Numeric),
    (Some(f32_on_stack), f64_promote_f32, Numeric),
    (Some(f32_on_stack), i32_reinterpret_f32, Numeric),
    (Some(f64_on_stack), i64_reinterpret_f64, Numeric),
    (Some(i32_on_stack), f32_reinterpret_i32, Numeric),
    (Some(i64_on_stack), f64_reinterpret_i64, Numeric),
    (Some(extendable_i32_on_stack), i32_extend_8_s, Numeric),
    (Some(extendable_i32_on_stack), i32_extend_16_s, Numeric),
    (Some(extendable_i64_on_stack), i64_extend_8_s, Numeric),
    (Some(extendable_i64_on_stack), i64_extend_16_s, Numeric),
    (Some(extendable_i64_on_stack), i64_extend_32_s, Numeric),
    (Some(nontrapping_f32_on_stack), i32_trunc_sat_f32_s, Numeric),
    (Some(nontrapping_f32_on_stack), i32_trunc_sat_f32_u, Numeric),
    (Some(nontrapping_f64_on_stack), i32_trunc_sat_f64_s, Numeric),
    (Some(nontrapping_f64_on_stack), i32_trunc_sat_f64_u, Numeric),
    (Some(nontrapping_f32_on_stack), i64_trunc_sat_f32_s, Numeric),
    (Some(nontrapping_f32_on_stack), i64_trunc_sat_f32_u, Numeric),
    (Some(nontrapping_f64_on_stack), i64_trunc_sat_f64_s, Numeric),
    (Some(nontrapping_f64_on_stack), i64_trunc_sat_f64_u, Numeric),
    // Reference instructions.
    (Some(ref_null_valid), ref_null, Reference),
    (Some(ref_func_valid), ref_func, Reference),
    (Some(ref_as_non_null_valid), ref_as_non_null, Reference),
    (Some(ref_eq_valid), ref_eq, Reference),
    (Some(ref_test_valid), ref_test, Reference),
    (Some(ref_cast_valid), ref_cast, Reference),
    (Some(ref_is_null_valid), ref_is_null, Reference),
    (Some(table_fill_valid), table_fill, Reference),
    (Some(table_set_valid), table_set, Reference),
    (Some(table_get_valid), table_get, Reference),
    (Some(table_size_valid), table_size, Reference),
    (Some(table_grow_valid), table_grow, Reference),
    (Some(table_copy_valid), table_copy, Reference),
    (Some(table_init_valid), table_init, Reference),
    (Some(elem_drop_valid), elem_drop, Reference),
    // Aggregate instructions.
    (Some(struct_new_valid), struct_new, Aggregate),
    (Some(struct_new_default_valid), struct_new_default, Aggregate),
    (Some(struct_get_valid), struct_get, Aggregate),
    (Some(struct_set_valid), struct_set, Aggregate),
    (Some(array_new_valid), array_new, Aggregate),
    (Some(array_new_fixed_valid), array_new_fixed, Aggregate),
    (Some(array_new_default_valid), array_new_default, Aggregate),
    (Some(array_new_data_valid), array_new_data, Aggregate),
    (Some(array_new_elem_valid), array_new_elem, Aggregate),
    (Some(array_get_valid), array_get, Aggregate),
    (Some(array_set_valid), array_set, Aggregate),
    (Some(array_len_valid), array_len, Aggregate),
    (Some(array_fill_valid), array_fill, Aggregate),
    (Some(array_copy_valid), array_copy, Aggregate),
    (Some(array_init_data_valid), array_init_data, Aggregate),
    (Some(array_init_elem_valid), array_init_elem, Aggregate),
    (Some(ref_i31_valid), ref_i31, Aggregate),
    (Some(i31_get_valid), i31_get, Aggregate),
    (Some(any_convert_extern_valid), any_convert_extern, Aggregate),
    (Some(extern_convert_any_valid), extern_convert_any, Aggregate),
    // SIMD instructions.
    (Some(simd_have_memory_and_offset), v128_load, Vector),
    (Some(simd_have_memory_and_offset), v128_load8x8s, Vector),
    (Some(simd_have_memory_and_offset), v128_load8x8u, Vector),
    (Some(simd_have_memory_and_offset), v128_load16x4s, Vector),
    (Some(simd_have_memory_and_offset), v128_load16x4u, Vector),
    (Some(simd_have_memory_and_offset), v128_load32x2s, Vector),
    (Some(simd_have_memory_and_offset), v128_load32x2u, Vector),
    (Some(simd_have_memory_and_offset), v128_load8_splat, Vector),
    (Some(simd_have_memory_and_offset), v128_load16_splat, Vector),
    (Some(simd_have_memory_and_offset), v128_load32_splat, Vector),
    (Some(simd_have_memory_and_offset), v128_load64_splat, Vector),
    (Some(simd_have_memory_and_offset), v128_load32_zero, Vector),
    (Some(simd_have_memory_and_offset), v128_load64_zero, Vector),
    (Some(simd_v128_store_valid), v128_store, Vector),
    (Some(simd_load_lane_valid), v128_load8_lane, Vector),
    (Some(simd_load_lane_valid), v128_load16_lane, Vector),
    (Some(simd_load_lane_valid), v128_load32_lane, Vector),
    (Some(simd_load_lane_valid), v128_load64_lane, Vector),
    (Some(simd_store_lane_valid), v128_store8_lane, Vector),
    (Some(simd_store_lane_valid), v128_store16_lane, Vector),
    (Some(simd_store_lane_valid), v128_store32_lane, Vector),
    (Some(simd_store_lane_valid), v128_store64_lane, Vector),
    (Some(simd_enabled), v128_const, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_shuffle, Vector),
    (Some(simd_v128_on_stack), i8x16_extract_lane_s, Vector),
    (Some(simd_v128_on_stack), i8x16_extract_lane_u, Vector),
    (Some(simd_v128_i32_on_stack), i8x16_replace_lane, Vector),
    (Some(simd_v128_on_stack), i16x8_extract_lane_s, Vector),
    (Some(simd_v128_on_stack), i16x8_extract_lane_u, Vector),
    (Some(simd_v128_i32_on_stack), i16x8_replace_lane, Vector),
    (Some(simd_v128_on_stack), i32x4_extract_lane, Vector),
    (Some(simd_v128_i32_on_stack), i32x4_replace_lane, Vector),
    (Some(simd_v128_on_stack), i64x2_extract_lane, Vector),
    (Some(simd_v128_i64_on_stack), i64x2_replace_lane, Vector),
    (Some(simd_v128_on_stack), f32x4_extract_lane, Vector),
    (Some(simd_v128_f32_on_stack), f32x4_replace_lane, Vector),
    (Some(simd_v128_on_stack), f64x2_extract_lane, Vector),
    (Some(simd_v128_f64_on_stack), f64x2_replace_lane, Vector),
    (Some(simd_i32_on_stack), i8x16_splat, Vector),
    (Some(simd_i32_on_stack), i16x8_splat, Vector),
    (Some(simd_i32_on_stack), i32x4_splat, Vector),
    (Some(simd_i64_on_stack), i64x2_splat, Vector),
    (Some(simd_f32_on_stack), f32x4_splat, Vector),
    (Some(simd_f64_on_stack), f64x2_splat, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_swizzle, Vector),
    (Some(simd_v128_v128_on_stack_relaxed), i8x16_relaxed_swizzle, Vector),
    (Some(simd_v128_v128_v128_on_stack), v128_bitselect, Vector),
    (Some(simd_v128_v128_v128_on_stack_relaxed), i8x16_relaxed_laneselect, Vector),
    (Some(simd_v128_v128_v128_on_stack_relaxed), i16x8_relaxed_laneselect, Vector),
    (Some(simd_v128_v128_v128_on_stack_relaxed), i32x4_relaxed_laneselect, Vector),
    (Some(simd_v128_v128_v128_on_stack_relaxed), i64x2_relaxed_laneselect, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_eq, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_ne, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_lt_s, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_lt_u, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_gt_s, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_gt_u, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_le_s, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_le_u, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_ge_s, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_ge_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_eq, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_ne, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_lt_s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_lt_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_gt_s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_gt_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_le_s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_le_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_ge_s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_ge_u, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_eq, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_ne, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_lt_s, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_lt_u, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_gt_s, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_gt_u, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_le_s, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_le_u, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_ge_s, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_ge_u, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_eq, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_ne, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_lt_s, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_gt_s, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_le_s, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_ge_s, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_eq, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_ne, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_lt, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_gt, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_le, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_ge, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_eq, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_ne, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_lt, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_gt, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_le, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_ge, Vector),
    (Some(simd_v128_on_stack), v128_not, Vector),
    (Some(simd_v128_v128_on_stack), v128_and, Vector),
    (Some(simd_v128_v128_on_stack), v128_and_not, Vector),
    (Some(simd_v128_v128_on_stack), v128_or, Vector),
    (Some(simd_v128_v128_on_stack), v128_xor, Vector),
    (Some(simd_v128_v128_on_stack), v128_any_true, Vector),
    (Some(simd_v128_on_stack), i8x16_abs, Vector),
    (Some(simd_v128_on_stack), i8x16_neg, Vector),
    (Some(simd_v128_on_stack), i8x16_popcnt, Vector),
    (Some(simd_v128_on_stack), i8x16_all_true, Vector),
    (Some(simd_v128_on_stack), i8x16_bitmask, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_narrow_i16x8s, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_narrow_i16x8u, Vector),
    (Some(simd_v128_i32_on_stack), i8x16_shl, Vector),
    (Some(simd_v128_i32_on_stack), i8x16_shr_s, Vector),
    (Some(simd_v128_i32_on_stack), i8x16_shr_u, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_add, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_add_sat_s, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_add_sat_u, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_sub, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_sub_sat_s, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_sub_sat_u, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_min_s, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_min_u, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_max_s, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_max_u, Vector),
    (Some(simd_v128_v128_on_stack), i8x16_avgr_u, Vector),
    (Some(simd_v128_on_stack), i16x8_extadd_pairwise_i8x16s, Vector),
    (Some(simd_v128_on_stack), i16x8_extadd_pairwise_i8x16u, Vector),
    (Some(simd_v128_on_stack), i16x8_abs, Vector),
    (Some(simd_v128_on_stack), i16x8_neg, Vector),
    (Some(simd_v128_v128_on_stack), i16x8q15_mulr_sat_s, Vector),
    (Some(simd_v128_on_stack), i16x8_all_true, Vector),
    (Some(simd_v128_on_stack), i16x8_bitmask, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_narrow_i32x4s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_narrow_i32x4u, Vector),
    (Some(simd_v128_on_stack), i16x8_extend_low_i8x16s, Vector),
    (Some(simd_v128_on_stack), i16x8_extend_high_i8x16s, Vector),
    (Some(simd_v128_on_stack), i16x8_extend_low_i8x16u, Vector),
    (Some(simd_v128_on_stack), i16x8_extend_high_i8x16u, Vector),
    (Some(simd_v128_i32_on_stack), i16x8_shl, Vector),
    (Some(simd_v128_i32_on_stack), i16x8_shr_s, Vector),
    (Some(simd_v128_i32_on_stack), i16x8_shr_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_add, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_add_sat_s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_add_sat_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_sub, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_sub_sat_s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_sub_sat_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_mul, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_min_s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_min_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_max_s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_max_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_avgr_u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_extmul_low_i8x16s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_extmul_high_i8x16s, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_extmul_low_i8x16u, Vector),
    (Some(simd_v128_v128_on_stack), i16x8_extmul_high_i8x16u, Vector),
    (Some(simd_v128_on_stack), i32x4_extadd_pairwise_i16x8s, Vector),
    (Some(simd_v128_on_stack), i32x4_extadd_pairwise_i16x8u, Vector),
    (Some(simd_v128_on_stack), i32x4_abs, Vector),
    (Some(simd_v128_on_stack), i32x4_neg, Vector),
    (Some(simd_v128_on_stack), i32x4_all_true, Vector),
    (Some(simd_v128_on_stack), i32x4_bitmask, Vector),
    (Some(simd_v128_on_stack), i32x4_extend_low_i16x8s, Vector),
    (Some(simd_v128_on_stack), i32x4_extend_high_i16x8s, Vector),
    (Some(simd_v128_on_stack), i32x4_extend_low_i16x8u, Vector),
    (Some(simd_v128_on_stack), i32x4_extend_high_i16x8u, Vector),
    (Some(simd_v128_i32_on_stack), i32x4_shl, Vector),
    (Some(simd_v128_i32_on_stack), i32x4_shr_s, Vector),
    (Some(simd_v128_i32_on_stack), i32x4_shr_u, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_add, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_sub, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_mul, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_min_s, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_min_u, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_max_s, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_max_u, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_dot_i16x8s, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_extmul_low_i16x8s, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_extmul_high_i16x8s, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_extmul_low_i16x8u, Vector),
    (Some(simd_v128_v128_on_stack), i32x4_extmul_high_i16x8u, Vector),
    (Some(simd_v128_on_stack), i64x2_abs, Vector),
    (Some(simd_v128_on_stack), i64x2_neg, Vector),
    (Some(simd_v128_on_stack), i64x2_all_true, Vector),
    (Some(simd_v128_on_stack), i64x2_bitmask, Vector),
    (Some(simd_v128_on_stack), i64x2_extend_low_i32x4s, Vector),
    (Some(simd_v128_on_stack), i64x2_extend_high_i32x4s, Vector),
    (Some(simd_v128_on_stack), i64x2_extend_low_i32x4u, Vector),
    (Some(simd_v128_on_stack), i64x2_extend_high_i32x4u, Vector),
    (Some(simd_v128_i32_on_stack), i64x2_shl, Vector),
    (Some(simd_v128_i32_on_stack), i64x2_shr_s, Vector),
    (Some(simd_v128_i32_on_stack), i64x2_shr_u, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_add, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_sub, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_mul, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_extmul_low_i32x4s, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_extmul_high_i32x4s, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_extmul_low_i32x4u, Vector),
    (Some(simd_v128_v128_on_stack), i64x2_extmul_high_i32x4u, Vector),
    (Some(simd_v128_on_stack), f32x4_ceil, Vector),
    (Some(simd_v128_on_stack), f32x4_floor, Vector),
    (Some(simd_v128_on_stack), f32x4_trunc, Vector),
    (Some(simd_v128_on_stack), f32x4_nearest, Vector),
    (Some(simd_v128_on_stack), f32x4_abs, Vector),
    (Some(simd_v128_on_stack), f32x4_neg, Vector),
    (Some(simd_v128_on_stack), f32x4_sqrt, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_add, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_sub, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_mul, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_div, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_min, Vector),
    (Some(simd_v128_v128_on_stack), f32x4_max, Vector),
    (Some(simd_v128_v128_on_stack), f32x4p_min, Vector),
    (Some(simd_v128_v128_on_stack), f32x4p_max, Vector),
    (Some(simd_v128_on_stack), f64x2_ceil, Vector),
    (Some(simd_v128_on_stack), f64x2_floor, Vector),
    (Some(simd_v128_on_stack), f64x2_trunc, Vector),
    (Some(simd_v128_on_stack), f64x2_nearest, Vector),
    (Some(simd_v128_on_stack), f64x2_abs, Vector),
    (Some(simd_v128_on_stack), f64x2_neg, Vector),
    (Some(simd_v128_on_stack), f64x2_sqrt, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_add, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_sub, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_mul, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_div, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_min, Vector),
    (Some(simd_v128_v128_on_stack), f64x2_max, Vector),
    (Some(simd_v128_v128_on_stack), f64x2p_min, Vector),
    (Some(simd_v128_v128_on_stack), f64x2p_max, Vector),
    (Some(simd_v128_on_stack), i32x4_trunc_sat_f32x4s, Vector),
    (Some(simd_v128_on_stack), i32x4_trunc_sat_f32x4u, Vector),
    (Some(simd_v128_on_stack), f32x4_convert_i32x4s, Vector),
    (Some(simd_v128_on_stack), f32x4_convert_i32x4u, Vector),
    (Some(simd_v128_on_stack), i32x4_trunc_sat_f64x2s_zero, Vector),
    (Some(simd_v128_on_stack), i32x4_trunc_sat_f64x2u_zero, Vector),
    (Some(simd_v128_on_stack), f64x2_convert_low_i32x4s, Vector),
    (Some(simd_v128_on_stack), f64x2_convert_low_i32x4u, Vector),
    (Some(simd_v128_on_stack), f32x4_demote_f64x2_zero, Vector),
    (Some(simd_v128_on_stack), f64x2_promote_low_f32x4, Vector),
    (Some(simd_v128_on_stack_relaxed), i32x4_relaxed_trunc_f32x4s, Vector),
    (Some(simd_v128_on_stack_relaxed), i32x4_relaxed_trunc_f32x4u, Vector),
    (Some(simd_v128_on_stack_relaxed), i32x4_relaxed_trunc_f64x2s_zero, Vector),
    (Some(simd_v128_on_stack_relaxed), i32x4_relaxed_trunc_f64x2u_zero, Vector),
    (Some(simd_v128_v128_v128_on_stack_relaxed), f32x4_relaxed_madd, Vector),
    (Some(simd_v128_v128_v128_on_stack_relaxed), f32x4_relaxed_nmadd, Vector),
    (Some(simd_v128_v128_v128_on_stack_relaxed), f64x2_relaxed_madd, Vector),
    (Some(simd_v128_v128_v128_on_stack_relaxed), f64x2_relaxed_nmadd, Vector),
    (Some(simd_v128_v128_on_stack_relaxed), f32x4_relaxed_min, Vector),
    (Some(simd_v128_v128_on_stack_relaxed), f32x4_relaxed_max, Vector),
    (Some(simd_v128_v128_on_stack_relaxed), f64x2_relaxed_min, Vector),
    (Some(simd_v128_v128_on_stack_relaxed), f64x2_relaxed_max, Vector),
    (Some(simd_v128_v128_on_stack_relaxed), i16x8_relaxed_q15mulr_s, Vector),
    (Some(simd_v128_v128_on_stack_relaxed), i16x8_relaxed_dot_i8x16_i7x16_s, Vector),
    (Some(simd_v128_v128_v128_on_stack_relaxed), i32x4_relaxed_dot_i8x16_i7x16_add_s, Vector),
}

pub(crate) struct CodeBuilderAllocations {
    // The control labels in scope right now.
    controls: Vec<Control>,

    // The types on the operand stack right now.
    operands: Vec<Option<ValType>>,

    // Dynamic set of options of instruction we can generate that are known to
    // be valid right now.
    options: Vec<(
        fn(&mut Unstructured, &Module, &mut CodeBuilder, &mut Vec<Instruction>) -> Result<()>,
        u32,
    )>,

    // Cached information about the module that we're generating functions for,
    // used to speed up validity checks. The mutable globals map is a map of the
    // type of global to the global indices which have that type (and they're
    // all mutable).
    mutable_globals: BTreeMap<ValType, Vec<u32>>,

    // Like mutable globals above this is a map from function types to the list
    // of functions that have that function type.
    functions: BTreeMap<Rc<FuncType>, Vec<u32>>,

    // Like functions above this is a map from tag types to the list of tags
    // have that tag type.
    tags: BTreeMap<Vec<ValType>, Vec<u32>>,

    // Tables in this module which have a funcref element type.
    table32_with_funcref: Vec<u32>,
    table64_with_funcref: Vec<u32>,

    // Functions that are referenced in the module through globals and segments.
    referenced_functions: Vec<u32>,

    // Precomputed tables/element segments that can be used for `table.init`,
    // stored as (segment, table).
    table32_init: Vec<(u32, u32)>,
    table64_init: Vec<(u32, u32)>,

    // Precomputed valid tables to copy between, stored in (src, dst) order.
    table_copy_32_to_32: Vec<(u32, u32)>,
    table_copy_32_to_64: Vec<(u32, u32)>,
    table_copy_64_to_32: Vec<(u32, u32)>,
    table_copy_64_to_64: Vec<(u32, u32)>,

    // Lists of table/memory indices which are either 32-bit or 64-bit. This is
    // used for faster lookup in validating instructions to know which memories
    // have which types. For example if there are no 64-bit memories then we
    // shouldn't ever look for i64 on the stack for `i32.load`.
    memory32: Vec<u32>,
    memory64: Vec<u32>,
    table32: Vec<u32>,
    table64: Vec<u32>,

    // State used when dropping operands to avoid dropping them into the ether
    // but instead folding their final values into module state, at this time
    // chosen to be exported globals.
    globals_cnt: u32,
    new_globals: Vec<(ValType, ConstExpr)>,
    global_dropped_i32: Option<u32>,
    global_dropped_i64: Option<u32>,
    global_dropped_f32: Option<u32>,
    global_dropped_f64: Option<u32>,
    global_dropped_v128: Option<u32>,

    // Indicates that additional exports cannot be generated. This will be true
    // if the `Config` specifies exactly which exports should be present.
    disallow_exporting: bool,
}

pub(crate) struct CodeBuilder<'a> {
    func_ty: &'a FuncType,
    locals: &'a mut Vec<ValType>,
    allocs: &'a mut CodeBuilderAllocations,

    // Temporary locals injected and used by nan canonicalization. Note that
    // this list of extra locals is appended to `self.locals` at the end of code
    // generation, and it's kept separate here to avoid using these locals in
    // `local.get` and similar instructions.
    extra_locals: Vec<ValType>,
    f32_scratch: Option<usize>,
    f64_scratch: Option<usize>,
    v128_scratch: Option<usize>,
}

/// A control frame.
#[derive(Debug, Clone)]
struct Control {
    kind: ControlKind,
    /// Value types that must be on the stack when entering this control frame.
    params: Vec<ValType>,
    /// Value types that are left on the stack when exiting this control frame.
    results: Vec<ValType>,
    /// How far down the operand stack instructions inside this control frame
    /// can reach.
    height: usize,
}

impl Control {
    fn label_types(&self) -> &[ValType] {
        if self.kind == ControlKind::Loop {
            &self.params
        } else {
            &self.results
        }
    }
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
enum ControlKind {
    Block,
    If,
    Loop,
    TryTable,
}

enum Float {
    F32,
    F64,
    F32x4,
    F64x2,
}

impl CodeBuilderAllocations {
    pub(crate) fn new(module: &Module, disallow_exporting: bool) -> Self {
        let mut mutable_globals = BTreeMap::new();
        for (i, global) in module.globals.iter().enumerate() {
            if global.mutable {
                mutable_globals
                    .entry(global.val_type)
                    .or_insert(Vec::new())
                    .push(i as u32);
            }
        }

        let mut tags = BTreeMap::new();
        for (idx, tag_type) in module.tags() {
            tags.entry(tag_type.func_type.params.to_vec())
                .or_insert(Vec::new())
                .push(idx);
        }

        let mut functions = BTreeMap::new();
        for (idx, func) in module.funcs() {
            functions
                .entry(func.clone())
                .or_insert(Vec::new())
                .push(idx);
        }

        let mut table32_with_funcref = Vec::new();
        let mut table64_with_funcref = Vec::new();
        let mut table32_tys = Vec::new();
        let mut table64_tys = Vec::new();
        for (i, table) in module.tables.iter().enumerate() {
            let funcref_dst = if table.table64 {
                table64_tys.push(table.element_type);
                &mut table64_with_funcref
            } else {
                table32_tys.push(table.element_type);
                &mut table32_with_funcref
            };
            if table.element_type == RefType::FUNCREF {
                funcref_dst.push(i as u32);
            }
        }

        let mut referenced_functions = BTreeSet::new();
        for (_, expr) in module.defined_globals.iter() {
            if let Some(i) = expr.get_ref_func() {
                referenced_functions.insert(i);
            }
        }

        let mut table32_init = Vec::new();
        let mut table64_init = Vec::new();
        for (i, g) in module.elems.iter().enumerate() {
            match &g.items {
                Elements::Expressions(e) => {
                    let iter = e.iter().filter_map(|e| e.get_ref_func());
                    referenced_functions.extend(iter);
                }
                Elements::Functions(e) => {
                    referenced_functions.extend(e.iter().cloned());
                }
            }
            for (j, table) in module.tables.iter().enumerate() {
                if module.ref_type_is_sub_type(g.ty, table.element_type) {
                    let dst = if table.table64 {
                        &mut table64_init
                    } else {
                        &mut table32_init
                    };
                    dst.push((i as u32, j as u32));
                }
            }
        }

        let mut memory32 = Vec::new();
        let mut memory64 = Vec::new();
        for (i, mem) in module.memories.iter().enumerate() {
            if mem.memory64 {
                memory64.push(i as u32);
            } else {
                memory32.push(i as u32);
            }
        }

        let mut table32 = Vec::new();
        let mut table64 = Vec::new();
        let mut table_copy_32_to_32 = Vec::new();
        let mut table_copy_32_to_64 = Vec::new();
        let mut table_copy_64_to_32 = Vec::new();
        let mut table_copy_64_to_64 = Vec::new();
        for (i, t) in module.tables.iter().enumerate() {
            if t.table64 {
                table64.push(i as u32);
            } else {
                table32.push(i as u32);
            }

            for (j, t2) in module.tables.iter().enumerate() {
                if module.val_type_is_sub_type(t.element_type.into(), t2.element_type.into()) {
                    let dst = match (t.table64, t2.table64) {
                        (false, false) => &mut table_copy_32_to_32,
                        (false, true) => &mut table_copy_32_to_64,
                        (true, false) => &mut table_copy_64_to_32,
                        (true, true) => &mut table_copy_64_to_64,
                    };
                    dst.push((i as u32, j as u32));
                }
            }
        }

        let mut global_dropped_i32 = None;
        let mut global_dropped_i64 = None;
        let mut global_dropped_f32 = None;
        let mut global_dropped_f64 = None;
        let mut global_dropped_v128 = None;

        // If we can't export additional globals, try to use existing exported
        // mutable globals for dropped values.
        if disallow_exporting {
            for (_, kind, index) in module.exports.iter() {
                if *kind == ExportKind::Global {
                    let ty = module.globals[*index as usize];
                    if ty.mutable {
                        match ty.val_type {
                            ValType::I32 => {
                                if global_dropped_i32.is_none() {
                                    global_dropped_i32 = Some(*index)
                                } else {
                                    global_dropped_f32 = Some(*index)
                                }
                            }
                            ValType::I64 => {
                                if global_dropped_i64.is_none() {
                                    global_dropped_i64 = Some(*index)
                                } else {
                                    global_dropped_f64 = Some(*index)
                                }
                            }
                            ValType::V128 => global_dropped_v128 = Some(*index),
                            _ => {}
                        }
                    }
                }
            }
        }

        CodeBuilderAllocations {
            controls: Vec::with_capacity(4),
            operands: Vec::with_capacity(16),
            options: Vec::with_capacity(NUM_OPTIONS),
            functions,
            tags,
            mutable_globals,
            table32_with_funcref,
            table64_with_funcref,
            referenced_functions: referenced_functions.into_iter().collect(),
            table32_init,
            table64_init,
            table_copy_32_to_32,
            table_copy_32_to_64,
            table_copy_64_to_32,
            table_copy_64_to_64,
            memory32,
            memory64,
            table32,
            table64,

            global_dropped_i32,
            global_dropped_i64,
            global_dropped_f32,
            global_dropped_f64,
            global_dropped_v128,
            globals_cnt: module.globals.len() as u32,
            new_globals: Vec::new(),
            disallow_exporting,
        }
    }

    pub(crate) fn builder<'a>(
        &'a mut self,
        func_ty: &'a FuncType,
        locals: &'a mut Vec<ValType>,
    ) -> CodeBuilder<'a> {
        self.controls.clear();
        self.controls.push(Control {
            kind: ControlKind::Block,
            params: vec![],
            results: func_ty.results.to_vec(),
            height: 0,
        });

        self.operands.clear();
        self.options.clear();

        CodeBuilder {
            func_ty,
            locals,
            allocs: self,
            extra_locals: Vec::new(),
            f32_scratch: None,
            f64_scratch: None,
            v128_scratch: None,
        }
    }

    pub fn finish(self, u: &mut Unstructured<'_>, module: &mut Module) -> arbitrary::Result<()> {
        // Any globals injected as part of dropping operands on the stack get
        // injected into the module here. Each global is then exported, most of
        // the time (if additional exports are allowed), to ensure it's part of
        // the "image" of this module available for differential execution for
        // example.
        for (ty, init) in self.new_globals {
            let global_idx = module.globals.len() as u32;
            module.globals.push(GlobalType {
                val_type: ty,
                mutable: true,
                shared: false,
            });
            module.defined_globals.push((global_idx, init));

            if self.disallow_exporting || u.ratio(1, 100).unwrap_or(false) {
                continue;
            }

            let name = unique_string(1_000, &mut module.export_names, u)?;
            module.add_arbitrary_export(name, ExportKind::Global, global_idx)?;
        }
        Ok(())
    }
}

impl CodeBuilder<'_> {
    fn pop_control(&mut self) -> Control {
        let control = self.allocs.controls.pop().unwrap();

        // Pop the actual types on the stack (which could be subtypes of the
        // declared types) and then push the declared types. This avoids us
        // accidentally generating code that relies on erased subtypes.
        for _ in &control.results {
            self.pop_operand();
        }
        for ty in &control.results {
            self.push_operand(Some(*ty));
        }

        control
    }

    fn push_control(
        &mut self,
        kind: ControlKind,
        params: impl Into<Vec<ValType>>,
        results: impl Into<Vec<ValType>>,
    ) {
        let params = params.into();
        let results = results.into();

        // Similar to in `pop_control`, we want to pop the actual argument types
        // off the stack (which could be subtypes of the declared parameter
        // types) and then push the parameter types. This effectively does type
        // erasure of any subtyping that exists so that we don't accidentally
        // generate code that relies on the specific subtypes.
        for _ in &params {
            self.pop_operand();
        }
        self.push_operands(&params);

        let height = self.allocs.operands.len() - params.len();
        self.allocs.controls.push(Control {
            kind,
            params,
            results,
            height,
        });
    }

    /// Get the operands that are in-scope within the current control frame.
    #[inline]
    fn operands(&self) -> &[Option<ValType>] {
        let height = self.allocs.controls.last().map_or(0, |c| c.height);
        &self.allocs.operands[height..]
    }

    /// Pop a single operand from the stack, regardless of expected type.
    #[inline]
    fn pop_operand(&mut self) -> Option<ValType> {
        self.allocs.operands.pop().unwrap()
    }

    #[inline]
    fn pop_operands(&mut self, module: &Module, to_pop: &[ValType]) {
        debug_assert!(self.types_on_stack(module, to_pop));
        self.allocs
            .operands
            .truncate(self.allocs.operands.len() - to_pop.len());
    }

    #[inline]
    fn push_operands(&mut self, to_push: &[ValType]) {
        self.allocs
            .operands
            .extend(to_push.iter().copied().map(Some));
    }

    #[inline]
    fn push_operand(&mut self, ty: Option<ValType>) {
        self.allocs.operands.push(ty);
    }

    fn pop_label_types(&mut self, module: &Module, target: u32) {
        let target = usize::try_from(target).unwrap();
        let control = &self.allocs.controls[self.allocs.controls.len() - 1 - target];
        debug_assert!(self.label_types_on_stack(module, control));
        self.allocs
            .operands
            .truncate(self.allocs.operands.len() - control.label_types().len());
    }

    fn push_label_types(&mut self, target: u32) {
        let target = usize::try_from(target).unwrap();
        let control = &self.allocs.controls[self.allocs.controls.len() - 1 - target];
        self.allocs
            .operands
            .extend(control.label_types().iter().copied().map(Some));
    }

    /// Pop the target label types, and then push them again.
    ///
    /// This is not a no-op due to subtyping: if we have a `T <: U` on the
    /// stack, and the target label's type is `[U]`, then this will erase the
    /// information about `T` and subsequent operations may only operate on `U`.
    fn pop_push_label_types(&mut self, module: &Module, target: u32) {
        self.pop_label_types(module, target);
        self.push_label_types(target)
    }

    fn label_types_on_stack(&self, module: &Module, to_check: &Control) -> bool {
        self.types_on_stack(module, to_check.label_types())
    }

    /// Is the given type on top of the stack?
    #[inline]
    fn type_on_stack(&self, module: &Module, ty: ValType) -> bool {
        self.type_on_stack_at(module, 0, ty)
    }

    /// Is the given type on the stack at the given index (indexing from the top
    /// of the stack towards the bottom).
    #[inline]
    fn type_on_stack_at(&self, module: &Module, at: usize, expected: ValType) -> bool {
        let operands = self.operands();
        if at >= operands.len() {
            return false;
        }
        match operands[operands.len() - 1 - at] {
            None => true,
            Some(actual) => module.val_type_is_sub_type(actual, expected),
        }
    }

    /// Are the given types on top of the stack?
    #[inline]
    fn types_on_stack(&self, module: &Module, types: &[ValType]) -> bool {
        self.operands().len() >= types.len()
            && types
                .iter()
                .rev()
                .enumerate()
                .all(|(idx, ty)| self.type_on_stack_at(module, idx, *ty))
    }

    /// Are the given field types on top of the stack?
    #[inline]
    fn field_types_on_stack(&self, module: &Module, types: &[FieldType]) -> bool {
        self.operands().len() >= types.len()
            && types
                .iter()
                .rev()
                .enumerate()
                .all(|(idx, ty)| self.type_on_stack_at(module, idx, ty.element_type.unpack()))
    }

    /// Is the given field type on top of the stack?
    #[inline]
    fn field_type_on_stack(&self, module: &Module, ty: FieldType) -> bool {
        self.type_on_stack(module, ty.element_type.unpack())
    }

    /// Is the given field type on the stack at the given position (indexed from
    /// the top of the stack)?
    #[inline]
    fn field_type_on_stack_at(&self, module: &Module, at: usize, ty: FieldType) -> bool {
        self.type_on_stack_at(module, at, ty.element_type.unpack())
    }

    /// Get the ref type on the top of the operand stack, if any.
    ///
    /// * `None` means no reftype on the stack.
    /// * `Some(None)` means that the stack is polymorphic.
    /// * `Some(Some(r))` means that `r` is the ref type on top of the stack.
    fn ref_type_on_stack(&self) -> Option<Option<RefType>> {
        match self.operands().last().copied()? {
            Some(ValType::Ref(r)) => Some(Some(r)),
            Some(_) => None,
            None => Some(None),
        }
    }

    /// Is there a `(ref null? <index>)` on the stack at the given position? If
    /// so return its nullability and type index.
    fn concrete_ref_type_on_stack_at(&self, at: usize) -> Option<(bool, u32)> {
        match self.operands().iter().copied().rev().nth(at)?? {
            ValType::Ref(RefType {
                nullable,
                heap_type: HeapType::Concrete(ty),
            }) => Some((nullable, ty)),
            _ => None,
        }
    }

    /// Is there a `(ref null? <index>)` at the given stack position that
    /// references a concrete array type?
    fn concrete_array_ref_type_on_stack_at(
        &self,
        module: &Module,
        at: usize,
    ) -> Option<(bool, u32, ArrayType)> {
        let (nullable, ty) = self.concrete_ref_type_on_stack_at(at)?;
        match &module.ty(ty).composite_type {
            CompositeType::Array(a) => Some((nullable, ty, *a)),
            _ => None,
        }
    }

    /// Is there a `(ref null? <index>)` at the given stack position that
    /// references a concrete struct type?
    fn concrete_struct_ref_type_on_stack_at<'a>(
        &self,
        module: &'a Module,
        at: usize,
    ) -> Option<(bool, u32, &'a StructType)> {
        let (nullable, ty) = self.concrete_ref_type_on_stack_at(at)?;
        match &module.ty(ty).composite_type {
            CompositeType::Struct(s) => Some((nullable, ty, s)),
            _ => None,
        }
    }

    /// Pop a reference type from the stack and return it.
    ///
    /// When in unreachable code and the stack is polymorphic, returns `None`.
    fn pop_ref_type(&mut self) -> Option<RefType> {
        let ref_ty = self.ref_type_on_stack().unwrap();
        self.pop_operand();
        ref_ty
    }

    /// Pops a `(ref null? <index>)` from the stack and return its nullability
    /// and type index.
    fn pop_concrete_ref_type(&mut self) -> (bool, u32) {
        let ref_ty = self.pop_ref_type().unwrap();
        match ref_ty.heap_type {
            HeapType::Concrete(i) => (ref_ty.nullable, i),
            _ => panic!("not a concrete ref type"),
        }
    }

    /// Get the `(ref null? <index>)` type on the top of the stack that
    /// references a function type, if any.
    fn concrete_funcref_on_stack(&self, module: &Module) -> Option<RefType> {
        match self.operands().last().copied()?? {
            ValType::Ref(r) => match r.heap_type {
                HeapType::Concrete(idx) => match &module.ty(idx).composite_type {
                    CompositeType::Func(_) => Some(r),
                    CompositeType::Struct(_) | CompositeType::Array(_) => None,
                },
                _ => None,
            },
            _ => None,
        }
    }

    /// Is there a `(ref null? <index>)` on the top of the stack that references
    /// a struct type with at least one field?
    fn non_empty_struct_ref_on_stack(&self, module: &Module, allow_null_refs: bool) -> bool {
        match self.operands().last() {
            Some(Some(ValType::Ref(RefType {
                nullable,
                heap_type: HeapType::Concrete(idx),
            }))) => match &module.ty(*idx).composite_type {
                CompositeType::Struct(s) => !s.fields.is_empty() && (!nullable || allow_null_refs),
                _ => false,
            },
            _ => false,
        }
    }

    #[inline(never)]
    fn arbitrary_block_type(&self, u: &mut Unstructured, module: &Module) -> Result<BlockType> {
        let mut options: Vec<Box<dyn Fn(&mut Unstructured) -> Result<BlockType>>> = vec![
            Box::new(|_| Ok(BlockType::Empty)),
            Box::new(|u| Ok(BlockType::Result(module.arbitrary_valtype(u)?))),
        ];
        if module.config.multi_value_enabled {
            for (i, ty) in module.func_types() {
                if self.types_on_stack(module, &ty.params) {
                    options.push(Box::new(move |_| Ok(BlockType::FunctionType(i as u32))));
                }
            }
        }
        let f = u.choose(&options)?;
        f(u)
    }

    pub(crate) fn arbitrary(
        mut self,
        u: &mut Unstructured,
        module: &Module,
    ) -> Result<Vec<Instruction>> {
        let max_instructions = module.config.max_instructions;
        let allowed_instructions = module.config.allowed_instructions;
        let mut instructions = vec![];

        while !self.allocs.controls.is_empty() {
            let keep_going = instructions.len() < max_instructions && u.arbitrary::<u8>()? != 0;
            if !keep_going {
                self.end_active_control_frames(
                    u,
                    module,
                    &mut instructions,
                    module.config.disallow_traps,
                )?;
                break;
            }

            match choose_instruction(u, module, allowed_instructions, &mut self) {
                Some(f) => {
                    f(u, module, &mut self, &mut instructions)?;
                }
                // Choosing an instruction can fail because there is not enough
                // underlying data, so we really cannot generate any more
                // instructions. In this case we swallow that error and instead
                // just terminate our wasm function's frames.
                None => {
                    self.end_active_control_frames(
                        u,
                        module,
                        &mut instructions,
                        module.config.disallow_traps,
                    )?;
                    break;
                }
            }

            // If the configuration for this module requests nan
            // canonicalization then perform that here based on whether or not
            // the previous instruction needs canonicalization. Note that this
            // is based off Cranelift's pass for nan canonicalization for which
            // instructions to canonicalize, but the general idea is most
            // floating-point operations.
            if module.config.canonicalize_nans {
                match instructions.last().unwrap() {
                    Instruction::F32Ceil
                    | Instruction::F32Floor
                    | Instruction::F32Nearest
                    | Instruction::F32Sqrt
                    | Instruction::F32Trunc
                    | Instruction::F32Div
                    | Instruction::F32Max
                    | Instruction::F32Min
                    | Instruction::F32Mul
                    | Instruction::F32Sub
                    | Instruction::F32Add => self.canonicalize_nan(Float::F32, &mut instructions),
                    Instruction::F64Ceil
                    | Instruction::F64Floor
                    | Instruction::F64Nearest
                    | Instruction::F64Sqrt
                    | Instruction::F64Trunc
                    | Instruction::F64Div
                    | Instruction::F64Max
                    | Instruction::F64Min
                    | Instruction::F64Mul
                    | Instruction::F64Sub
                    | Instruction::F64Add => self.canonicalize_nan(Float::F64, &mut instructions),
                    Instruction::F32x4Ceil
                    | Instruction::F32x4Floor
                    | Instruction::F32x4Nearest
                    | Instruction::F32x4Sqrt
                    | Instruction::F32x4Trunc
                    | Instruction::F32x4Div
                    | Instruction::F32x4Max
                    | Instruction::F32x4Min
                    | Instruction::F32x4Mul
                    | Instruction::F32x4Sub
                    | Instruction::F32x4Add => {
                        self.canonicalize_nan(Float::F32x4, &mut instructions)
                    }
                    Instruction::F64x2Ceil
                    | Instruction::F64x2Floor
                    | Instruction::F64x2Nearest
                    | Instruction::F64x2Sqrt
                    | Instruction::F64x2Trunc
                    | Instruction::F64x2Div
                    | Instruction::F64x2Max
                    | Instruction::F64x2Min
                    | Instruction::F64x2Mul
                    | Instruction::F64x2Sub
                    | Instruction::F64x2Add => {
                        self.canonicalize_nan(Float::F64x2, &mut instructions)
                    }
                    _ => {}
                }
            }
        }

        self.locals.extend(self.extra_locals.drain(..));

        Ok(instructions)
    }

    fn canonicalize_nan(&mut self, ty: Float, ins: &mut Vec<Instruction>) {
        // We'll need to temporarily save the top of the stack into a local, so
        // figure out that local here. Note that this tries to use the same
        // local if canonicalization happens more than once in a function.
        let (local, val_ty) = match ty {
            Float::F32 => (&mut self.f32_scratch, ValType::F32),
            Float::F64 => (&mut self.f64_scratch, ValType::F64),
            Float::F32x4 | Float::F64x2 => (&mut self.v128_scratch, ValType::V128),
        };
        let local = match *local {
            Some(i) => i as u32,
            None => self.alloc_local(val_ty),
        };

        // Save the previous instruction's result into a local. This also leaves
        // a value on the stack as `val1` for the `select` instruction.
        ins.push(Instruction::LocalTee(local));

        // The `val2` value input to the `select` below, our nan pattern.
        //
        // The nan patterns here are chosen to be a canonical representation
        // which is still NaN but the wasm will always produce the same bits of
        // a nan so if the wasm takes a look at the nan inside it'll always see
        // the same representation.
        const CANON_32BIT_NAN: u32 = 0b01111111110000000000000000000000;
        const CANON_64BIT_NAN: u64 =
            0b0111111111111000000000000000000000000000000000000000000000000000;
        ins.push(match ty {
            Float::F32 => Instruction::F32Const(f32::from_bits(CANON_32BIT_NAN)),
            Float::F64 => Instruction::F64Const(f64::from_bits(CANON_64BIT_NAN)),
            Float::F32x4 => {
                let nan = CANON_32BIT_NAN as i128;
                let nan = nan | (nan << 32) | (nan << 64) | (nan << 96);
                Instruction::V128Const(nan)
            }
            Float::F64x2 => {
                let nan = CANON_64BIT_NAN as i128;
                let nan = nan | (nan << 64);
                Instruction::V128Const(nan)
            }
        });

        // the condition of the `select`, which is the float's equality test
        // with itself.
        ins.push(Instruction::LocalGet(local));
        ins.push(Instruction::LocalGet(local));
        ins.push(match ty {
            Float::F32 => Instruction::F32Eq,
            Float::F64 => Instruction::F64Eq,
            Float::F32x4 => Instruction::F32x4Eq,
            Float::F64x2 => Instruction::F64x2Eq,
        });

        // Select the result. If the condition is nonzero (aka the float is
        // equal to itself) it picks `val1`, otherwise if zero (aka the float
        // is nan) it picks `val2`.
        ins.push(match ty {
            Float::F32 | Float::F64 => Instruction::Select,
            Float::F32x4 | Float::F64x2 => Instruction::V128Bitselect,
        });
    }

    fn alloc_local(&mut self, ty: ValType) -> u32 {
        let val = self.locals.len() + self.func_ty.params.len() + self.extra_locals.len();
        self.extra_locals.push(ty);
        u32::try_from(val).unwrap()
    }

    fn end_active_control_frames(
        &mut self,
        u: &mut Unstructured<'_>,
        module: &Module,
        instructions: &mut Vec<Instruction>,
        disallow_traps: bool,
    ) -> Result<()> {
        while !self.allocs.controls.is_empty() {
            // Ensure that this label is valid by placing the right types onto
            // the operand stack for the end of the label.
            self.guarantee_label_results(u, module, instructions, disallow_traps)?;

            // Remove the label and clear the operand stack since the label has
            // been removed.
            let label = self.allocs.controls.pop().unwrap();
            self.allocs.operands.truncate(label.height);

            // If this is an `if` that is not stack neutral, then it
            // must have an `else`. Generate synthetic results here in the same
            // manner we did above.
            if label.kind == ControlKind::If && label.params != label.results {
                instructions.push(Instruction::Else);
                self.allocs.controls.push(label.clone());
                self.allocs
                    .operands
                    .extend(label.params.into_iter().map(Some));
                self.guarantee_label_results(u, module, instructions, disallow_traps)?;
                self.allocs.controls.pop();
                self.allocs.operands.truncate(label.height);
            }

            // The last control frame for the function return does not
            // need an `end` instruction.
            if !self.allocs.controls.is_empty() {
                instructions.push(Instruction::End);
            }

            // Place the results of the label onto the operand stack for use
            // after the label.
            self.allocs
                .operands
                .extend(label.results.into_iter().map(Some));
        }
        Ok(())
    }

    /// Modifies the instruction stream to guarantee that the current control
    /// label's results are on the stack and ready for the control label to return.
    fn guarantee_label_results(
        &mut self,
        u: &mut Unstructured<'_>,
        module: &Module,
        instructions: &mut Vec<Instruction>,
        disallow_traps: bool,
    ) -> Result<()> {
        let operands = self.operands();
        let label = self.allocs.controls.last().unwrap();

        // Already done, yay!
        if label.results.len() == operands.len() && self.types_on_stack(module, &label.results) {
            return Ok(());
        }

        // Generating an unreachable instruction is always a valid way to
        // generate any types for a label, but it's not too interesting, so
        // don't favor it.
        if !disallow_traps && u.ratio(1, u16::MAX)? {
            instructions.push(Instruction::Unreachable);
            return Ok(());
        }

        // Arbitrarily massage the stack to get the expected results. First we
        // drop all extraneous results to we're only dealing with those we want
        // to deal with. Afterwards we start at the bottom of the stack and move
        // up, figuring out what matches and what doesn't. As soon as something
        // doesn't match we throw out that and everything else remaining,
        // filling in results with dummy values.
        let operands = operands.to_vec();
        let mut operands = operands.as_slice();
        let label_results = label.results.to_vec();
        while operands.len() > label_results.len() {
            self.drop_operand(u, *operands.last().unwrap(), instructions)?;
            operands = &operands[..operands.len() - 1];
        }
        for (i, expected) in label_results.iter().enumerate() {
            if let Some(actual) = operands.get(i) {
                if Some(*expected) == *actual {
                    continue;
                }
                for ty in operands[i..].iter().rev() {
                    self.drop_operand(u, *ty, instructions)?;
                }
                operands = &[];
            }
            instructions.push(module.arbitrary_const_instruction(*expected, u)?);
        }
        Ok(())
    }

    fn drop_operand(
        &mut self,
        u: &mut Unstructured<'_>,
        ty: Option<ValType>,
        instructions: &mut Vec<Instruction>,
    ) -> Result<()> {
        if !self.mix_operand_into_global(u, ty, instructions)? {
            instructions.push(Instruction::Drop);
        }
        Ok(())
    }

    /// Attempts to drop the top operand on the stack by "mixing" it into a
    /// global.
    ///
    /// This is done to avoid dropping values on the floor to ensure that
    /// everything is part of some computation somewhere. Otherwise, for
    /// example, most function results are dropped on the floor as the stack
    /// won't happen to match the function type that we're generating.
    ///
    /// This will return `true` if the operand has been dropped, and `false` if
    /// it didn't for one reason or another.
    fn mix_operand_into_global(
        &mut self,
        u: &mut Unstructured<'_>,
        ty: Option<ValType>,
        instructions: &mut Vec<Instruction>,
    ) -> Result<bool> {
        // If the type of this operand isn't known, for example if it's relevant
        // to unreachable code, then it can't be combined, so return `false`.
        let ty = match ty {
            Some(ty) => ty,
            None => return Ok(false),
        };

        // Use the input stream to allow a small chance of dropping the value
        // without combining it.
        if u.ratio(1, 100)? {
            return Ok(false);
        }

        // Depending on the type lookup or inject a global to place this value
        // into.
        let (global, combine) = match ty {
            ValType::I32 => {
                let global = *self.allocs.global_dropped_i32.get_or_insert_with(|| {
                    self.allocs.new_globals.push((ty, ConstExpr::i32_const(0)));
                    inc(&mut self.allocs.globals_cnt)
                });
                (global, Instruction::I32Xor)
            }
            ValType::I64 => {
                let global = *self.allocs.global_dropped_i64.get_or_insert_with(|| {
                    self.allocs.new_globals.push((ty, ConstExpr::i64_const(0)));
                    inc(&mut self.allocs.globals_cnt)
                });
                (global, Instruction::I64Xor)
            }
            ValType::F32 => {
                let global = *self.allocs.global_dropped_f32.get_or_insert_with(|| {
                    self.allocs
                        .new_globals
                        .push((ValType::I32, ConstExpr::i32_const(0)));
                    inc(&mut self.allocs.globals_cnt)
                });
                instructions.push(Instruction::I32ReinterpretF32);
                (global, Instruction::I32Xor)
            }
            ValType::F64 => {
                let global = *self.allocs.global_dropped_f64.get_or_insert_with(|| {
                    self.allocs
                        .new_globals
                        .push((ValType::I64, ConstExpr::i64_const(0)));
                    inc(&mut self.allocs.globals_cnt)
                });
                instructions.push(Instruction::I64ReinterpretF64);
                (global, Instruction::I64Xor)
            }
            ValType::V128 => {
                let global = *self.allocs.global_dropped_v128.get_or_insert_with(|| {
                    self.allocs.new_globals.push((ty, ConstExpr::v128_const(0)));
                    inc(&mut self.allocs.globals_cnt)
                });
                (global, Instruction::V128Xor)
            }

            // Don't know how to combine reference types at this time, so just
            // let it get dropped.
            ValType::Ref(_) => return Ok(false),
        };
        instructions.push(Instruction::GlobalGet(global));
        instructions.push(combine);
        instructions.push(Instruction::GlobalSet(global));

        return Ok(true);

        fn inc(val: &mut u32) -> u32 {
            let ret = *val;
            *val += 1;
            ret
        }
    }
}

#[inline]
fn unreachable_valid(module: &Module, _: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
}

fn unreachable(
    _: &mut Unstructured,
    _: &Module,
    _: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    instructions.push(Instruction::Unreachable);
    Ok(())
}

fn nop(
    _: &mut Unstructured,
    _: &Module,
    _: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    instructions.push(Instruction::Nop);
    Ok(())
}

fn block(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let block_ty = builder.arbitrary_block_type(u, module)?;
    let (params, results) = module.params_results(&block_ty);
    builder.push_control(ControlKind::Block, params, results);
    instructions.push(Instruction::Block(block_ty));
    Ok(())
}

#[inline]
fn try_table_valid(module: &Module, _: &mut CodeBuilder) -> bool {
    module.config.exceptions_enabled
}

fn try_table(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let block_ty = builder.arbitrary_block_type(u, module)?;

    let mut catch_options: Vec<
        Box<dyn Fn(&mut Unstructured<'_>, &mut CodeBuilder<'_>) -> Result<Catch>>,
    > = Vec::new();

    for (i, ctrl) in builder.allocs.controls.iter().rev().enumerate() {
        let i = i as u32;

        let label_types = ctrl.label_types();

        // Empty labels are candidates for a `catch_all` since nothing is
        // pushed in that case.
        if label_types.is_empty() {
            catch_options.push(Box::new(move |_, _| Ok(Catch::All { label: i })));
        }

        // Labels with just an `externref` are suitable for `catch_all_refs`,
        // which first pushes nothing since there's no tag and then pushes
        // the caught exception value.
        if label_types == [ValType::EXNREF] {
            catch_options.push(Box::new(move |_, _| Ok(Catch::AllRef { label: i })));
        }

        // If there is a tag which exactly matches the types of the label we're
        // looking at then that tag can be used as part of a `catch` branch.
        // That tag's parameters, which are the except values, are pushed
        // for the label.
        if builder.allocs.tags.contains_key(label_types) {
            let label_types = label_types.to_vec();
            catch_options.push(Box::new(move |u, builder| {
                Ok(Catch::One {
                    tag: *u.choose(&builder.allocs.tags[&label_types])?,
                    label: i,
                })
            }));
        }

        // And finally the last type of catch label, `catch_ref`. If the label
        // ends with `exnref`, then use everything except the last `exnref` to
        // see if there's a matching tag. If so then `catch_ref` can be used
        // with that tag when branching to this label.
        if let Some((&ValType::EXNREF, rest)) = label_types.split_last() {
            if builder.allocs.tags.contains_key(rest) {
                let rest = rest.to_vec();
                catch_options.push(Box::new(move |u, builder| {
                    Ok(Catch::OneRef {
                        tag: *u.choose(&builder.allocs.tags[&rest])?,
                        label: i,
                    })
                }));
            }
        }
    }

    let mut catches = Vec::new();
    if catch_options.len() > 0 {
        for _ in 0..u.int_in_range(0..=10)? {
            catches.push(u.choose(&mut catch_options)?(u, builder)?);
        }
    }

    let (params, results) = module.params_results(&block_ty);
    builder.push_control(ControlKind::TryTable, params, results);

    instructions.push(Instruction::TryTable(block_ty, catches.into()));
    Ok(())
}

fn r#loop(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let block_ty = builder.arbitrary_block_type(u, module)?;
    let (params, results) = module.params_results(&block_ty);
    builder.push_control(ControlKind::Loop, params, results);
    instructions.push(Instruction::Loop(block_ty));
    Ok(())
}

#[inline]
fn if_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.type_on_stack(module, ValType::I32)
}

fn r#if(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    let block_ty = builder.arbitrary_block_type(u, module)?;
    let (params, results) = module.params_results(&block_ty);
    builder.push_control(ControlKind::If, params, results);
    instructions.push(Instruction::If(block_ty));
    Ok(())
}

#[inline]
fn else_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    let last_control = builder.allocs.controls.last().unwrap();
    last_control.kind == ControlKind::If
        && builder.operands().len() == last_control.results.len()
        && builder.types_on_stack(module, &last_control.results)
}

fn r#else(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let control = builder.pop_control();
    builder.pop_operands(module, &control.results);
    builder.push_operands(&control.params);
    builder.push_control(ControlKind::Block, control.params, control.results);
    instructions.push(Instruction::Else);
    Ok(())
}

#[inline]
fn end_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    // Note: first control frame is the function return's control frame, which
    // does not have an associated `end`.
    if builder.allocs.controls.len() <= 1 {
        return false;
    }
    let control = builder.allocs.controls.last().unwrap();
    builder.operands().len() == control.results.len()
        && builder.types_on_stack(module, &control.results)
        // `if`s that don't leave the stack as they found it must have an
        // `else`.
        && !(control.kind == ControlKind::If && control.params != control.results)
}

fn end(
    _: &mut Unstructured,
    _: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_control();
    instructions.push(Instruction::End);
    Ok(())
}

#[inline]
fn br_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder
        .allocs
        .controls
        .iter()
        .any(|l| builder.label_types_on_stack(module, l))
}

fn br(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = builder
        .allocs
        .controls
        .iter()
        .filter(|l| builder.label_types_on_stack(module, l))
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let (target, _) = builder
        .allocs
        .controls
        .iter()
        .rev()
        .enumerate()
        .filter(|(_, l)| builder.label_types_on_stack(module, l))
        .nth(i)
        .unwrap();
    let target = u32::try_from(target).unwrap();
    builder.pop_label_types(module, target);
    instructions.push(Instruction::Br(target));
    Ok(())
}

#[inline]
fn br_if_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !builder.type_on_stack(module, ValType::I32) {
        return false;
    }
    let ty = builder.allocs.operands.pop().unwrap();
    let is_valid = builder
        .allocs
        .controls
        .iter()
        .any(|l| builder.label_types_on_stack(module, l));
    builder.allocs.operands.push(ty);
    is_valid
}

fn br_if(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);

    let n = builder
        .allocs
        .controls
        .iter()
        .filter(|l| builder.label_types_on_stack(module, l))
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let (target, _) = builder
        .allocs
        .controls
        .iter()
        .rev()
        .enumerate()
        .filter(|(_, l)| builder.label_types_on_stack(module, l))
        .nth(i)
        .unwrap();
    let target = u32::try_from(target).unwrap();
    builder.pop_push_label_types(module, target);
    instructions.push(Instruction::BrIf(target));
    Ok(())
}

#[inline]
fn br_table_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !builder.type_on_stack(module, ValType::I32) {
        return false;
    }
    let ty = builder.allocs.operands.pop().unwrap();
    let is_valid = br_valid(module, builder);
    builder.allocs.operands.push(ty);
    is_valid
}

fn br_table(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);

    let n = builder
        .allocs
        .controls
        .iter()
        .filter(|l| builder.label_types_on_stack(module, l))
        .count();
    debug_assert!(n > 0);

    let i = u.int_in_range(0..=n - 1)?;
    let (default_target, _) = builder
        .allocs
        .controls
        .iter()
        .rev()
        .enumerate()
        .filter(|(_, l)| builder.label_types_on_stack(module, l))
        .nth(i)
        .unwrap();
    let control = &builder.allocs.controls[builder.allocs.controls.len() - 1 - default_target];

    let targets = builder
        .allocs
        .controls
        .iter()
        .rev()
        .enumerate()
        .filter(|(_, l)| l.label_types() == control.label_types())
        .map(|(t, _)| t as u32)
        .collect();

    let tys = control.label_types().to_vec();
    builder.pop_operands(module, &tys);

    instructions.push(Instruction::BrTable(targets, default_target as u32));
    Ok(())
}

#[inline]
fn return_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.label_types_on_stack(module, &builder.allocs.controls[0])
}

fn r#return(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let results = builder.allocs.controls[0].results.clone();
    builder.pop_operands(module, &results);
    instructions.push(Instruction::Return);
    Ok(())
}

#[inline]
fn call_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder
        .allocs
        .functions
        .keys()
        .any(|func_ty| builder.types_on_stack(module, &func_ty.params))
}

fn call(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let candidates = builder
        .allocs
        .functions
        .iter()
        .filter(|(func_ty, _)| builder.types_on_stack(module, &func_ty.params))
        .flat_map(|(_, v)| v.iter().copied())
        .collect::<Vec<_>>();
    assert!(candidates.len() > 0);
    let i = u.int_in_range(0..=candidates.len() - 1)?;
    let (func_idx, ty) = module.funcs().nth(candidates[i] as usize).unwrap();
    builder.pop_operands(module, &ty.params);
    builder.push_operands(&ty.results);
    instructions.push(Instruction::Call(func_idx as u32));
    Ok(())
}

#[inline]
fn call_ref_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.gc_enabled {
        return false;
    }
    let funcref = match builder.concrete_funcref_on_stack(module) {
        Some(f) => f,
        None => return false,
    };
    if module.config.disallow_traps && funcref.nullable {
        return false;
    }
    match funcref.heap_type {
        HeapType::Concrete(idx) => {
            let ty = builder.allocs.operands.pop().unwrap();
            let params = &module.ty(idx).unwrap_func().params;
            let valid = builder.types_on_stack(module, params);
            builder.allocs.operands.push(ty);
            valid
        }
        _ => unreachable!(),
    }
}

fn call_ref(
    _u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let heap_ty = match builder.pop_operand() {
        Some(ValType::Ref(r)) => r.heap_type,
        _ => unreachable!(),
    };
    let idx = match heap_ty {
        HeapType::Concrete(idx) => idx,
        _ => unreachable!(),
    };
    let func_ty = match &module.ty(idx).composite_type {
        CompositeType::Func(f) => f,
        _ => unreachable!(),
    };
    builder.pop_operands(module, &func_ty.params);
    builder.push_operands(&func_ty.results);
    instructions.push(Instruction::CallRef(idx));
    Ok(())
}

#[inline]
fn call_indirect_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if module.config.disallow_traps {
        // We have no way to reflect, at run time, on a `funcref` in
        // the `i`th slot in a table and dynamically avoid trapping
        // `call_indirect`s. Therefore, we can't emit *any*
        // `call_indirect` instructions if we want to avoid traps.
        return false;
    }
    let can_call32 = builder.type_on_stack(module, ValType::I32)
        && builder.allocs.table32_with_funcref.len() > 0;
    let can_call64 = builder.type_on_stack(module, ValType::I64)
        && builder.allocs.table64_with_funcref.len() > 0;
    if !can_call32 && !can_call64 {
        return false;
    }
    let ty = builder.allocs.operands.pop().unwrap();
    let is_valid = module
        .func_types()
        .any(|(_, ty)| builder.types_on_stack(module, &ty.params));
    builder.allocs.operands.push(ty);
    is_valid
}

fn call_indirect(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let table = select_call_indirect_table(u, module, builder)?;

    let choices = module
        .func_types()
        .filter(|(_, ty)| builder.types_on_stack(module, &ty.params))
        .collect::<Vec<_>>();
    let (type_idx, ty) = u.choose(&choices)?;
    builder.pop_operands(module, &ty.params);
    builder.push_operands(&ty.results);
    instructions.push(Instruction::CallIndirect {
        ty: *type_idx as u32,
        table,
    });
    Ok(())
}

fn select_call_indirect_table(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
) -> Result<u32> {
    let tables = if builder.type_on_stack(module, ValType::I32) {
        builder.pop_operands(module, &[ValType::I32]);
        &builder.allocs.table32_with_funcref
    } else {
        builder.pop_operands(module, &[ValType::I64]);
        &builder.allocs.table64_with_funcref
    };
    Ok(*u.choose(tables)?)
}

#[inline]
fn return_call_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.tail_call_enabled {
        return false;
    }

    builder.allocs.functions.keys().any(|func_ty| {
        builder.types_on_stack(module, &func_ty.params)
            && builder.allocs.controls[0].label_types() == &func_ty.results
    })
}

fn return_call(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let candidates = builder
        .allocs
        .functions
        .iter()
        .filter(|(func_ty, _)| {
            builder.types_on_stack(module, &func_ty.params)
                && builder.allocs.controls[0].label_types() == &func_ty.results
        })
        .flat_map(|(_, v)| v.iter().copied())
        .collect::<Vec<_>>();
    assert!(candidates.len() > 0);
    let i = u.int_in_range(0..=candidates.len() - 1)?;
    let (func_idx, ty) = module.funcs().nth(candidates[i] as usize).unwrap();
    builder.pop_operands(module, &ty.params);
    builder.push_operands(&ty.results);
    instructions.push(Instruction::ReturnCall(func_idx as u32));
    Ok(())
}

#[inline]
fn return_call_ref_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.gc_enabled {
        return false;
    }

    let ref_ty = match builder.concrete_funcref_on_stack(module) {
        None => return false,
        Some(r) if r.nullable && module.config.disallow_traps => return false,
        Some(r) => r,
    };

    let idx = match ref_ty.heap_type {
        HeapType::Concrete(idx) => idx,
        _ => unreachable!(),
    };
    let func_ty = match &module.ty(idx).composite_type {
        CompositeType::Func(f) => f,
        CompositeType::Array(_) | CompositeType::Struct(_) => return false,
    };

    let ty = builder.allocs.operands.pop().unwrap();
    let valid = builder.types_on_stack(module, &func_ty.params)
        && builder.func_ty.results == func_ty.results;
    builder.allocs.operands.push(ty);
    valid
}

fn return_call_ref(
    _u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let heap_ty = match builder.pop_operand() {
        Some(ValType::Ref(r)) => r.heap_type,
        _ => unreachable!(),
    };
    let idx = match heap_ty {
        HeapType::Concrete(idx) => idx,
        _ => unreachable!(),
    };
    let func_ty = match &module.ty(idx).composite_type {
        CompositeType::Func(f) => f,
        _ => unreachable!(),
    };
    builder.pop_operands(module, &func_ty.params);
    builder.push_operands(&func_ty.results);
    instructions.push(Instruction::ReturnCallRef(idx));
    Ok(())
}

#[inline]
fn return_call_indirect_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.tail_call_enabled {
        return false;
    }

    call_indirect_valid(module, builder)
}

fn return_call_indirect(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let table = select_call_indirect_table(u, module, builder)?;

    let choices = module
        .func_types()
        .filter(|(_, ty)| {
            builder.types_on_stack(module, &ty.params)
                && builder.allocs.controls[0].label_types() == &ty.results
        })
        .collect::<Vec<_>>();
    let (type_idx, ty) = u.choose(&choices)?;
    builder.pop_operands(module, &ty.params);
    builder.push_operands(&ty.results);
    instructions.push(Instruction::ReturnCallIndirect {
        ty: *type_idx as u32,
        table,
    });
    Ok(())
}

#[inline]
fn throw_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.exceptions_enabled
        && builder
            .allocs
            .tags
            .keys()
            .any(|k| builder.types_on_stack(module, k))
}

fn throw(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let candidates = builder
        .allocs
        .tags
        .iter()
        .filter(|(k, _)| builder.types_on_stack(module, k))
        .flat_map(|(_, v)| v.iter().copied())
        .collect::<Vec<_>>();
    assert!(candidates.len() > 0);
    let i = u.int_in_range(0..=candidates.len() - 1)?;
    let (tag_idx, tag_type) = module.tags().nth(candidates[i] as usize).unwrap();
    // Tags have no results, throwing cannot return
    assert!(tag_type.func_type.results.len() == 0);
    builder.pop_operands(module, &tag_type.func_type.params);
    instructions.push(Instruction::Throw(tag_idx as u32));
    Ok(())
}

#[inline]
fn throw_ref_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.exceptions_enabled && builder.types_on_stack(module, &[ValType::EXNREF])
}

fn throw_ref(
    _u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::EXNREF]);
    instructions.push(Instruction::ThrowRef);
    Ok(())
}

#[inline]
fn br_on_null_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.gc_enabled {
        return false;
    }
    if builder.ref_type_on_stack().is_none() {
        return false;
    }
    let ty = builder.allocs.operands.pop().unwrap();
    let valid = br_valid(module, builder);
    builder.allocs.operands.push(ty);
    valid
}

fn br_on_null(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let heap_type = match builder.pop_ref_type() {
        Some(r) => r.heap_type,
        None => {
            if !module.types.is_empty() && u.arbitrary()? {
                HeapType::Concrete(u.int_in_range(0..=u32::try_from(module.types.len()).unwrap())?)
            } else {
                *u.choose(&[
                    HeapType::Func,
                    HeapType::Extern,
                    HeapType::Any,
                    HeapType::None,
                    HeapType::NoExtern,
                    HeapType::NoFunc,
                    HeapType::Eq,
                    HeapType::Struct,
                    HeapType::Array,
                    HeapType::I31,
                ])?
            }
        }
    };

    let n = builder
        .allocs
        .controls
        .iter()
        .filter(|l| builder.label_types_on_stack(module, l))
        .count();
    debug_assert!(n > 0);

    let i = u.int_in_range(0..=n - 1)?;
    let (target, _) = builder
        .allocs
        .controls
        .iter()
        .rev()
        .enumerate()
        .filter(|(_, l)| builder.label_types_on_stack(module, l))
        .nth(i)
        .unwrap();
    let target = u32::try_from(target).unwrap();

    builder.pop_push_label_types(module, target);
    builder.push_operands(&[ValType::Ref(RefType {
        nullable: false,
        heap_type,
    })]);

    instructions.push(Instruction::BrOnNull(target));
    Ok(())
}

fn is_valid_br_on_non_null_control(
    module: &Module,
    control: &Control,
    builder: &CodeBuilder,
) -> bool {
    let ref_ty = match control.label_types().last() {
        Some(ValType::Ref(r)) => *r,
        Some(_) | None => return false,
    };
    let nullable_ref_ty = RefType {
        nullable: true,
        ..ref_ty
    };
    builder.type_on_stack(module, ValType::Ref(nullable_ref_ty))
        && control
            .label_types()
            .iter()
            .rev()
            .enumerate()
            .skip(1)
            .all(|(idx, ty)| builder.type_on_stack_at(module, idx, *ty))
}

#[inline]
fn br_on_non_null_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && builder
            .allocs
            .controls
            .iter()
            .any(|l| is_valid_br_on_non_null_control(module, l, builder))
}

fn br_on_non_null(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = builder
        .allocs
        .controls
        .iter()
        .filter(|l| is_valid_br_on_non_null_control(module, l, builder))
        .count();
    debug_assert!(n > 0);

    let i = u.int_in_range(0..=n - 1)?;
    let (target, _) = builder
        .allocs
        .controls
        .iter()
        .rev()
        .enumerate()
        .filter(|(_, l)| is_valid_br_on_non_null_control(module, l, builder))
        .nth(i)
        .unwrap();
    let target = u32::try_from(target).unwrap();

    builder.pop_push_label_types(module, target);
    builder.pop_ref_type();
    instructions.push(Instruction::BrOnNonNull(target));
    Ok(())
}

fn is_valid_br_on_cast_control(
    module: &Module,
    builder: &CodeBuilder,
    control: &Control,
    from_ref_ty: Option<RefType>,
) -> bool {
    // The last label type is a sub type of the type we are casting from...
    let to_ref_ty = match control.label_types().last() {
        Some(ValType::Ref(r)) => *r,
        _ => return false,
    };
    if let Some(from_ty) = from_ref_ty {
        if !module.ref_type_is_sub_type(to_ref_ty, from_ty) {
            return false;
        }
    }
    // ... and the rest of the label types are on the stack.
    control
        .label_types()
        .iter()
        .rev()
        .enumerate()
        .skip(1)
        .all(|(idx, ty)| builder.type_on_stack_at(module, idx, *ty))
}

#[inline]
fn br_on_cast_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    let from_ref_ty = match builder.ref_type_on_stack() {
        None => return false,
        Some(r) => r,
    };
    module.config.gc_enabled
        && builder
            .allocs
            .controls
            .iter()
            .any(|l| is_valid_br_on_cast_control(module, builder, l, from_ref_ty))
}

/// Compute the [type difference] between the two given ref types.
///
/// [type difference]: https://webassembly.github.io/gc/core/valid/conventions.html#aux-reftypediff
fn ref_type_difference(a: RefType, b: RefType) -> RefType {
    RefType {
        nullable: if b.nullable { false } else { a.nullable },
        heap_type: a.heap_type,
    }
}

fn br_on_cast(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let from_ref_type = builder.ref_type_on_stack().unwrap();

    let n = builder
        .allocs
        .controls
        .iter()
        .filter(|l| is_valid_br_on_cast_control(module, builder, l, from_ref_type))
        .count();
    debug_assert!(n > 0);

    let i = u.int_in_range(0..=n - 1)?;
    let (relative_depth, control) = builder
        .allocs
        .controls
        .iter()
        .rev()
        .enumerate()
        .filter(|(_, l)| is_valid_br_on_cast_control(module, builder, l, from_ref_type))
        .nth(i)
        .unwrap();
    let relative_depth = u32::try_from(relative_depth).unwrap();

    let num_label_types = control.label_types().len();
    let to_ref_type = match control.label_types().last() {
        Some(ValType::Ref(r)) => *r,
        _ => unreachable!(),
    };

    let to_ref_type = module.arbitrary_matching_ref_type(u, to_ref_type)?;
    let from_ref_type = from_ref_type.unwrap_or(to_ref_type);
    let from_ref_type = module.arbitrary_super_type_of_ref_type(u, from_ref_type)?;

    // Do `pop_push_label_types` but without its debug assert that the types are
    // on the stack, since we know that we have a `from_ref_type` but the label
    // requires a `to_ref_type`.
    for _ in 0..num_label_types {
        builder.pop_operand();
    }
    builder.push_label_types(relative_depth);

    // Replace the label's `to_ref_type` with the type difference.
    builder.pop_operand();
    builder.push_operands(&[ValType::Ref(ref_type_difference(
        from_ref_type,
        to_ref_type,
    ))]);

    instructions.push(Instruction::BrOnCast {
        from_ref_type,
        to_ref_type,
        relative_depth,
    });
    Ok(())
}

fn is_valid_br_on_cast_fail_control(
    module: &Module,
    builder: &CodeBuilder,
    control: &Control,
    from_ref_type: Option<RefType>,
) -> bool {
    control
        .label_types()
        .last()
        .map_or(false, |label_ty| match (label_ty, from_ref_type) {
            (ValType::Ref(label_ty), Some(from_ty)) => {
                module.ref_type_is_sub_type(from_ty, *label_ty)
            }
            (ValType::Ref(_), None) => true,
            _ => false,
        })
        && control
            .label_types()
            .iter()
            .rev()
            .enumerate()
            .skip(1)
            .all(|(idx, ty)| builder.type_on_stack_at(module, idx, *ty))
}

#[inline]
fn br_on_cast_fail_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    let from_ref_ty = match builder.ref_type_on_stack() {
        None => return false,
        Some(r) => r,
    };
    module.config.gc_enabled
        && builder
            .allocs
            .controls
            .iter()
            .any(|l| is_valid_br_on_cast_fail_control(module, builder, l, from_ref_ty))
}

fn br_on_cast_fail(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let from_ref_type = builder.ref_type_on_stack().unwrap();

    let n = builder
        .allocs
        .controls
        .iter()
        .filter(|l| is_valid_br_on_cast_fail_control(module, builder, l, from_ref_type))
        .count();
    debug_assert!(n > 0);

    let i = u.int_in_range(0..=n - 1)?;
    let (relative_depth, control) = builder
        .allocs
        .controls
        .iter()
        .rev()
        .enumerate()
        .filter(|(_, l)| is_valid_br_on_cast_fail_control(module, builder, l, from_ref_type))
        .nth(i)
        .unwrap();
    let relative_depth = u32::try_from(relative_depth).unwrap();

    let from_ref_type =
        from_ref_type.unwrap_or_else(|| match control.label_types().last().unwrap() {
            ValType::Ref(r) => *r,
            _ => unreachable!(),
        });
    let to_ref_type = module.arbitrary_matching_ref_type(u, from_ref_type)?;

    // Pop-push the label types and then replace its last reference type with
    // our `to_ref_type`.
    builder.pop_push_label_types(module, relative_depth);
    builder.pop_operand();
    builder.push_operand(Some(ValType::Ref(to_ref_type)));

    instructions.push(Instruction::BrOnCastFail {
        from_ref_type,
        to_ref_type,
        relative_depth,
    });
    Ok(())
}

#[inline]
fn drop_valid(_module: &Module, builder: &mut CodeBuilder) -> bool {
    !builder.operands().is_empty()
}

fn drop(
    u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let ty = builder.pop_operand();
    builder.drop_operand(u, ty, instructions)?;
    Ok(())
}

#[inline]
fn select_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !(builder.operands().len() >= 3 && builder.type_on_stack(module, ValType::I32)) {
        return false;
    }
    let t = builder.operands()[builder.operands().len() - 2];
    let u = builder.operands()[builder.operands().len() - 3];
    t.is_none() || u.is_none() || t == u
}

fn select(
    _: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    let t = builder.pop_operand();
    let u = builder.pop_operand();
    let ty = t.or(u);
    builder.allocs.operands.push(ty);
    match ty {
        Some(ty @ ValType::Ref(_)) => instructions.push(Instruction::TypedSelect(ty)),
        Some(ValType::I32) | Some(ValType::I64) | Some(ValType::F32) | Some(ValType::F64)
        | Some(ValType::V128) | None => instructions.push(Instruction::Select),
    }
    Ok(())
}

#[inline]
fn local_get_valid(_module: &Module, builder: &mut CodeBuilder) -> bool {
    !builder.func_ty.params.is_empty() || !builder.locals.is_empty()
}

fn local_get(
    u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let num_params = builder.func_ty.params.len();
    let n = num_params + builder.locals.len();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    builder.allocs.operands.push(Some(if i < num_params {
        builder.func_ty.params[i]
    } else {
        builder.locals[i - num_params]
    }));
    instructions.push(Instruction::LocalGet(i as u32));
    Ok(())
}

#[inline]
fn local_set_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder
        .func_ty
        .params
        .iter()
        .chain(builder.locals.iter())
        .any(|ty| builder.type_on_stack(module, *ty))
}

fn local_set(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = builder
        .func_ty
        .params
        .iter()
        .chain(builder.locals.iter())
        .filter(|ty| builder.type_on_stack(module, **ty))
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let (j, _) = builder
        .func_ty
        .params
        .iter()
        .chain(builder.locals.iter())
        .enumerate()
        .filter(|(_, ty)| builder.type_on_stack(module, **ty))
        .nth(i)
        .unwrap();
    builder.allocs.operands.pop();
    instructions.push(Instruction::LocalSet(j as u32));
    Ok(())
}

fn local_tee(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = builder
        .func_ty
        .params
        .iter()
        .chain(builder.locals.iter())
        .filter(|ty| builder.type_on_stack(module, **ty))
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let (j, ty) = builder
        .func_ty
        .params
        .iter()
        .chain(builder.locals.iter())
        .enumerate()
        .filter(|(_, ty)| builder.type_on_stack(module, **ty))
        .nth(i)
        .unwrap();
    builder.allocs.operands.pop();
    instructions.push(Instruction::LocalTee(j as u32));
    builder.push_operand(Some(*ty));
    Ok(())
}

#[inline]
fn global_get_valid(module: &Module, _: &mut CodeBuilder) -> bool {
    module.globals.len() > 0
}

fn global_get(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    debug_assert!(module.globals.len() > 0);
    let global_idx = u.int_in_range(0..=module.globals.len() - 1)?;
    builder
        .allocs
        .operands
        .push(Some(module.globals[global_idx].val_type));
    instructions.push(Instruction::GlobalGet(global_idx as u32));
    Ok(())
}

#[inline]
fn global_set_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder
        .allocs
        .mutable_globals
        .iter()
        .any(|(ty, _)| builder.type_on_stack(module, *ty))
}

fn global_set(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let candidates = builder
        .allocs
        .mutable_globals
        .iter()
        .find(|(ty, _)| builder.type_on_stack(module, **ty))
        .unwrap()
        .1;
    let i = u.int_in_range(0..=candidates.len() - 1)?;
    builder.allocs.operands.pop();
    instructions.push(Instruction::GlobalSet(candidates[i]));
    Ok(())
}

#[inline]
fn have_memory(module: &Module, _: &mut CodeBuilder) -> bool {
    module.memories.len() > 0
}

#[inline]
fn have_memory_and_offset(module: &Module, builder: &mut CodeBuilder) -> bool {
    (builder.allocs.memory32.len() > 0 && builder.type_on_stack(module, ValType::I32))
        || (builder.allocs.memory64.len() > 0 && builder.type_on_stack(module, ValType::I64))
}

#[inline]
fn have_data(module: &Module, _: &mut CodeBuilder) -> bool {
    module.data.len() > 0
}

fn i32_load(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1, 2])?;
    builder.allocs.operands.push(Some(ValType::I32));
    if module.config.disallow_traps {
        no_traps::load(Instruction::I32Load(memarg), module, builder, instructions);
    } else {
        instructions.push(Instruction::I32Load(memarg));
    }
    Ok(())
}

fn i64_load(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1, 2, 3])?;
    builder.allocs.operands.push(Some(ValType::I64));
    if module.config.disallow_traps {
        no_traps::load(Instruction::I64Load(memarg), module, builder, instructions);
    } else {
        instructions.push(Instruction::I64Load(memarg));
    }
    Ok(())
}

fn f32_load(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1, 2])?;
    builder.allocs.operands.push(Some(ValType::F32));
    if module.config.disallow_traps {
        no_traps::load(Instruction::F32Load(memarg), module, builder, instructions);
    } else {
        instructions.push(Instruction::F32Load(memarg));
    }
    Ok(())
}

fn f64_load(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1, 2, 3])?;
    builder.allocs.operands.push(Some(ValType::F64));
    if module.config.disallow_traps {
        no_traps::load(Instruction::F64Load(memarg), module, builder, instructions);
    } else {
        instructions.push(Instruction::F64Load(memarg));
    }
    Ok(())
}

fn i32_load_8_s(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0])?;
    builder.allocs.operands.push(Some(ValType::I32));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I32Load8S(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I32Load8S(memarg));
    }
    Ok(())
}

fn i32_load_8_u(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0])?;
    builder.allocs.operands.push(Some(ValType::I32));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I32Load8U(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I32Load8U(memarg));
    }
    Ok(())
}

fn i32_load_16_s(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1])?;
    builder.allocs.operands.push(Some(ValType::I32));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I32Load16S(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I32Load16S(memarg));
    }
    Ok(())
}

fn i32_load_16_u(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1])?;
    builder.allocs.operands.push(Some(ValType::I32));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I32Load16U(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I32Load16U(memarg));
    }
    Ok(())
}

fn i64_load_8_s(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0])?;
    builder.allocs.operands.push(Some(ValType::I64));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I64Load8S(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I64Load8S(memarg));
    }
    Ok(())
}

fn i64_load_16_s(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1])?;
    builder.allocs.operands.push(Some(ValType::I64));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I64Load16S(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I64Load16S(memarg));
    }
    Ok(())
}

fn i64_load_32_s(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1, 2])?;
    builder.allocs.operands.push(Some(ValType::I64));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I64Load32S(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I64Load32S(memarg));
    }
    Ok(())
}

fn i64_load_8_u(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0])?;
    builder.allocs.operands.push(Some(ValType::I64));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I64Load8U(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I64Load8U(memarg));
    }
    Ok(())
}

fn i64_load_16_u(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1])?;
    builder.allocs.operands.push(Some(ValType::I64));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I64Load16U(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I64Load16U(memarg));
    }
    Ok(())
}

fn i64_load_32_u(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let memarg = mem_arg(u, module, builder, &[0, 1, 2])?;
    builder.allocs.operands.push(Some(ValType::I64));
    if module.config.disallow_traps {
        no_traps::load(
            Instruction::I64Load32U(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I64Load32U(memarg));
    }
    Ok(())
}

#[inline]
fn store_valid(module: &Module, builder: &mut CodeBuilder, f: impl Fn() -> ValType) -> bool {
    (builder.allocs.memory32.len() > 0 && builder.types_on_stack(module, &[ValType::I32, f()]))
        || (builder.allocs.memory64.len() > 0
            && builder.types_on_stack(module, &[ValType::I64, f()]))
}

#[inline]
fn i32_store_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    store_valid(module, builder, || ValType::I32)
}

fn i32_store(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    let memarg = mem_arg(u, module, builder, &[0, 1, 2])?;
    if module.config.disallow_traps {
        no_traps::store(Instruction::I32Store(memarg), module, builder, instructions);
    } else {
        instructions.push(Instruction::I32Store(memarg));
    }
    Ok(())
}

#[inline]
fn i64_store_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    store_valid(module, builder, || ValType::I64)
}

fn i64_store(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    let memarg = mem_arg(u, module, builder, &[0, 1, 2, 3])?;
    if module.config.disallow_traps {
        no_traps::store(Instruction::I64Store(memarg), module, builder, instructions);
    } else {
        instructions.push(Instruction::I64Store(memarg));
    }
    Ok(())
}

#[inline]
fn f32_store_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    store_valid(module, builder, || ValType::F32)
}

fn f32_store(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    let memarg = mem_arg(u, module, builder, &[0, 1, 2])?;
    if module.config.disallow_traps {
        no_traps::store(Instruction::F32Store(memarg), module, builder, instructions);
    } else {
        instructions.push(Instruction::F32Store(memarg));
    }
    Ok(())
}

#[inline]
fn f64_store_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    store_valid(module, builder, || ValType::F64)
}

fn f64_store(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    let memarg = mem_arg(u, module, builder, &[0, 1, 2, 3])?;
    if module.config.disallow_traps {
        no_traps::store(Instruction::F64Store(memarg), module, builder, instructions);
    } else {
        instructions.push(Instruction::F64Store(memarg));
    }
    Ok(())
}

fn i32_store_8(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    let memarg = mem_arg(u, module, builder, &[0])?;
    if module.config.disallow_traps {
        no_traps::store(
            Instruction::I32Store8(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I32Store8(memarg));
    }
    Ok(())
}

fn i32_store_16(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    let memarg = mem_arg(u, module, builder, &[0, 1])?;
    if module.config.disallow_traps {
        no_traps::store(
            Instruction::I32Store16(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I32Store16(memarg));
    }
    Ok(())
}

fn i64_store_8(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    let memarg = mem_arg(u, module, builder, &[0])?;
    if module.config.disallow_traps {
        no_traps::store(
            Instruction::I64Store8(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I64Store8(memarg));
    }
    Ok(())
}

fn i64_store_16(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    let memarg = mem_arg(u, module, builder, &[0, 1])?;
    if module.config.disallow_traps {
        no_traps::store(
            Instruction::I64Store16(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I64Store16(memarg));
    }
    Ok(())
}

fn i64_store_32(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    let memarg = mem_arg(u, module, builder, &[0, 1, 2])?;
    if module.config.disallow_traps {
        no_traps::store(
            Instruction::I64Store32(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::I64Store32(memarg));
    }
    Ok(())
}

fn memory_size(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let i = u.int_in_range(0..=module.memories.len() - 1)?;
    let ty = if module.memories[i].memory64 {
        ValType::I64
    } else {
        ValType::I32
    };
    builder.push_operands(&[ty]);
    instructions.push(Instruction::MemorySize(i as u32));
    Ok(())
}

#[inline]
fn memory_grow_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    (builder.allocs.memory32.len() > 0 && builder.type_on_stack(module, ValType::I32))
        || (builder.allocs.memory64.len() > 0 && builder.type_on_stack(module, ValType::I64))
}

fn memory_grow(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let ty = if builder.type_on_stack(module, ValType::I32) {
        ValType::I32
    } else {
        ValType::I64
    };
    let index = memory_index(u, builder, ty)?;
    builder.pop_operands(module, &[ty]);
    builder.push_operands(&[ty]);
    instructions.push(Instruction::MemoryGrow(index));
    Ok(())
}

#[inline]
fn memory_init_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.bulk_memory_enabled
        && have_data(module, builder)
        && !module.config.disallow_traps // Non-trapping memory init not yet implemented
        && (builder.allocs.memory32.len() > 0
            && builder.types_on_stack(module, &[ValType::I32, ValType::I32, ValType::I32])
            || (builder.allocs.memory64.len() > 0
                && builder.types_on_stack(module, &[ValType::I64, ValType::I32, ValType::I32])))
}

fn memory_init(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    let ty = if builder.type_on_stack(module, ValType::I32) {
        ValType::I32
    } else {
        ValType::I64
    };
    let mem = memory_index(u, builder, ty)?;
    let data_index = data_index(u, module)?;
    builder.pop_operands(module, &[ty]);
    instructions.push(Instruction::MemoryInit { mem, data_index });
    Ok(())
}

#[inline]
fn memory_fill_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.bulk_memory_enabled
        && !module.config.disallow_traps // Non-trapping memory fill generation not yet implemented
        && (builder.allocs.memory32.len() > 0
            && builder.types_on_stack(module, &[ValType::I32, ValType::I32, ValType::I32])
            || (builder.allocs.memory64.len() > 0
                && builder.types_on_stack(module, &[ValType::I64, ValType::I32, ValType::I64])))
}

fn memory_fill(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let ty = if builder.type_on_stack(module, ValType::I32) {
        ValType::I32
    } else {
        ValType::I64
    };
    let mem = memory_index(u, builder, ty)?;
    builder.pop_operands(module, &[ty, ValType::I32, ty]);
    instructions.push(Instruction::MemoryFill(mem));
    Ok(())
}

#[inline]
fn memory_copy_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.bulk_memory_enabled {
        return false;
    }

    // The non-trapping case for memory copy has not yet been implemented,
    // so we are excluding them for now
    if module.config.disallow_traps {
        return false;
    }

    let n32 = builder.allocs.memory32.len();
    let n64 = builder.allocs.memory64.len();

    if builder.types_on_stack(module, &[ValType::I64, ValType::I64, ValType::I64]) && n64 > 0 {
        return true;
    }
    if builder.types_on_stack(module, &[ValType::I32, ValType::I32, ValType::I32]) && n32 > 0 {
        return true;
    }
    if builder.types_on_stack(module, &[ValType::I64, ValType::I32, ValType::I32])
        && n32 > 0
        && n64 > 0
    {
        return true;
    }
    if builder.types_on_stack(module, &[ValType::I32, ValType::I64, ValType::I32])
        && n32 > 0
        && n64 > 0
    {
        return true;
    }

    false
}

fn memory_copy(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let (src, dst) = gen_copy_src_and_dst(module, builder);
    let src_mem = src.choose(u, &builder.allocs.memory32, &builder.allocs.memory64)?;
    let dst_mem = dst.choose(u, &builder.allocs.memory32, &builder.allocs.memory64)?;
    instructions.push(Instruction::MemoryCopy { dst_mem, src_mem });
    Ok(())
}

enum CopyIndexSize {
    I32,
    I64,
}

impl CopyIndexSize {
    fn choose(&self, u: &mut Unstructured<'_>, n32: &[u32], n64: &[u32]) -> Result<u32> {
        Ok(match self {
            CopyIndexSize::I32 => *u.choose(n32)?,
            CopyIndexSize::I64 => *u.choose(n64)?,
        })
    }
}

fn gen_copy_src_and_dst(
    module: &Module,
    builder: &mut CodeBuilder,
) -> (CopyIndexSize, CopyIndexSize) {
    if builder.types_on_stack(module, &[ValType::I64, ValType::I64, ValType::I64]) {
        builder.pop_operands(module, &[ValType::I64, ValType::I64, ValType::I64]);
        (CopyIndexSize::I64, CopyIndexSize::I64)
    } else if builder.types_on_stack(module, &[ValType::I32, ValType::I32, ValType::I32]) {
        builder.pop_operands(module, &[ValType::I32, ValType::I32, ValType::I32]);
        (CopyIndexSize::I32, CopyIndexSize::I32)
    } else if builder.types_on_stack(module, &[ValType::I64, ValType::I32, ValType::I32]) {
        builder.pop_operands(module, &[ValType::I64, ValType::I32, ValType::I32]);
        (CopyIndexSize::I32, CopyIndexSize::I64)
    } else if builder.types_on_stack(module, &[ValType::I32, ValType::I64, ValType::I32]) {
        builder.pop_operands(module, &[ValType::I32, ValType::I64, ValType::I32]);
        (CopyIndexSize::I64, CopyIndexSize::I32)
    } else {
        unreachable!()
    }
}

#[inline]
fn data_drop_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    have_data(module, builder) && module.config.bulk_memory_enabled
}

fn data_drop(
    u: &mut Unstructured,
    module: &Module,
    _builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    instructions.push(Instruction::DataDrop(data_index(u, module)?));
    Ok(())
}

fn i32_const(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.push_operands(&[ValType::I32]);
    instructions.push(module.arbitrary_const_instruction(ValType::I32, u)?);
    Ok(())
}

fn i64_const(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.push_operands(&[ValType::I64]);
    instructions.push(module.arbitrary_const_instruction(ValType::I64, u)?);
    Ok(())
}

fn f32_const(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.push_operands(&[ValType::F32]);
    instructions.push(module.arbitrary_const_instruction(ValType::F32, u)?);
    Ok(())
}

fn f64_const(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.push_operands(&[ValType::F64]);
    instructions.push(module.arbitrary_const_instruction(ValType::F64, u)?);
    Ok(())
}

#[inline]
fn i32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.type_on_stack(module, ValType::I32)
}

fn i32_eqz(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Eqz);
    Ok(())
}

#[inline]
fn i32_i32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.types_on_stack(module, &[ValType::I32, ValType::I32])
}

fn i32_eq(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Eq);
    Ok(())
}

fn i32_ne(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Ne);
    Ok(())
}

fn i32_lt_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32LtS);
    Ok(())
}

fn i32_lt_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32LtU);
    Ok(())
}

fn i32_gt_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32GtS);
    Ok(())
}

fn i32_gt_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32GtU);
    Ok(())
}

fn i32_le_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32LeS);
    Ok(())
}

fn i32_le_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32LeU);
    Ok(())
}

fn i32_ge_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32GeS);
    Ok(())
}

fn i32_ge_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32GeU);
    Ok(())
}

#[inline]
fn i64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.types_on_stack(module, &[ValType::I64])
}

fn i64_eqz(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64Eqz);
    Ok(())
}

#[inline]
fn i64_i64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.types_on_stack(module, &[ValType::I64, ValType::I64])
}

fn i64_eq(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64Eq);
    Ok(())
}

fn i64_ne(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64Ne);
    Ok(())
}

fn i64_lt_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64LtS);
    Ok(())
}

fn i64_lt_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64LtU);
    Ok(())
}

fn i64_gt_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64GtS);
    Ok(())
}

fn i64_gt_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64GtU);
    Ok(())
}

fn i64_le_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64LeS);
    Ok(())
}

fn i64_le_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64LeU);
    Ok(())
}

fn i64_ge_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64GeS);
    Ok(())
}

fn i64_ge_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I64GeU);
    Ok(())
}

fn f32_f32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.types_on_stack(module, &[ValType::F32, ValType::F32])
}

fn f32_eq(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F32Eq);
    Ok(())
}

fn f32_ne(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F32Ne);
    Ok(())
}

fn f32_lt(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F32Lt);
    Ok(())
}

fn f32_gt(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F32Gt);
    Ok(())
}

fn f32_le(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F32Le);
    Ok(())
}

fn f32_ge(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F32Ge);
    Ok(())
}

fn f64_f64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.types_on_stack(module, &[ValType::F64, ValType::F64])
}

fn f64_eq(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F64Eq);
    Ok(())
}

fn f64_ne(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F64Ne);
    Ok(())
}

fn f64_lt(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F64Lt);
    Ok(())
}

fn f64_gt(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F64Gt);
    Ok(())
}

fn f64_le(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F64Le);
    Ok(())
}

fn f64_ge(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::F64Ge);
    Ok(())
}

fn i32_clz(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Clz);
    Ok(())
}

fn i32_ctz(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Ctz);
    Ok(())
}

fn i32_popcnt(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Popcnt);
    Ok(())
}

fn i32_add(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Add);
    Ok(())
}

fn i32_sub(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Sub);
    Ok(())
}

fn i32_mul(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Mul);
    Ok(())
}

fn i32_div_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    if module.config.disallow_traps {
        no_traps::signed_div_rem(Instruction::I32DivS, builder, instructions);
    } else {
        instructions.push(Instruction::I32DivS);
    }
    Ok(())
}

fn i32_div_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    if module.config.disallow_traps {
        no_traps::unsigned_div_rem(Instruction::I32DivU, builder, instructions);
    } else {
        instructions.push(Instruction::I32DivU);
    }
    Ok(())
}

fn i32_rem_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    if module.config.disallow_traps {
        no_traps::signed_div_rem(Instruction::I32RemS, builder, instructions);
    } else {
        instructions.push(Instruction::I32RemS);
    }
    Ok(())
}

fn i32_rem_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    if module.config.disallow_traps {
        no_traps::unsigned_div_rem(Instruction::I32RemU, builder, instructions);
    } else {
        instructions.push(Instruction::I32RemU);
    }
    Ok(())
}

fn i32_and(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32And);
    Ok(())
}

fn i32_or(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Or);
    Ok(())
}

fn i32_xor(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Xor);
    Ok(())
}

fn i32_shl(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Shl);
    Ok(())
}

fn i32_shr_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32ShrS);
    Ok(())
}

fn i32_shr_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32ShrU);
    Ok(())
}

fn i32_rotl(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Rotl);
    Ok(())
}

fn i32_rotr(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32, ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Rotr);
    Ok(())
}

fn i64_clz(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Clz);
    Ok(())
}

fn i64_ctz(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Ctz);
    Ok(())
}

fn i64_popcnt(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Popcnt);
    Ok(())
}

fn i64_add(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Add);
    Ok(())
}

fn i64_sub(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Sub);
    Ok(())
}

fn i64_mul(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Mul);
    Ok(())
}

fn i64_div_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    if module.config.disallow_traps {
        no_traps::signed_div_rem(Instruction::I64DivS, builder, instructions);
    } else {
        instructions.push(Instruction::I64DivS);
    }
    Ok(())
}

fn i64_div_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    if module.config.disallow_traps {
        no_traps::unsigned_div_rem(Instruction::I64DivU, builder, instructions);
    } else {
        instructions.push(Instruction::I64DivU);
    }
    Ok(())
}

fn i64_rem_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    if module.config.disallow_traps {
        no_traps::signed_div_rem(Instruction::I64RemS, builder, instructions);
    } else {
        instructions.push(Instruction::I64RemS);
    }
    Ok(())
}

fn i64_rem_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    if module.config.disallow_traps {
        no_traps::unsigned_div_rem(Instruction::I64RemU, builder, instructions);
    } else {
        instructions.push(Instruction::I64RemU);
    }
    Ok(())
}

fn i64_and(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64And);
    Ok(())
}

fn i64_or(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Or);
    Ok(())
}

fn i64_xor(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Xor);
    Ok(())
}

fn i64_shl(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Shl);
    Ok(())
}

fn i64_shr_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64ShrS);
    Ok(())
}

fn i64_shr_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64ShrU);
    Ok(())
}

fn i64_rotl(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Rotl);
    Ok(())
}

fn i64_rotr(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64, ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Rotr);
    Ok(())
}

#[inline]
fn f32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.types_on_stack(module, &[ValType::F32])
}

fn f32_abs(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Abs);
    Ok(())
}

fn f32_neg(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Neg);
    Ok(())
}

fn f32_ceil(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Ceil);
    Ok(())
}

fn f32_floor(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Floor);
    Ok(())
}

fn f32_trunc(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Trunc);
    Ok(())
}

fn f32_nearest(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Nearest);
    Ok(())
}

fn f32_sqrt(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Sqrt);
    Ok(())
}

fn f32_add(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Add);
    Ok(())
}

fn f32_sub(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Sub);
    Ok(())
}

fn f32_mul(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Mul);
    Ok(())
}

fn f32_div(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Div);
    Ok(())
}

fn f32_min(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Min);
    Ok(())
}

fn f32_max(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Max);
    Ok(())
}

fn f32_copysign(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32, ValType::F32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32Copysign);
    Ok(())
}

#[inline]
fn f64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    builder.types_on_stack(module, &[ValType::F64])
}

fn f64_abs(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Abs);
    Ok(())
}

fn f64_neg(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Neg);
    Ok(())
}

fn f64_ceil(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Ceil);
    Ok(())
}

fn f64_floor(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Floor);
    Ok(())
}

fn f64_trunc(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Trunc);
    Ok(())
}

fn f64_nearest(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Nearest);
    Ok(())
}

fn f64_sqrt(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Sqrt);
    Ok(())
}

fn f64_add(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Add);
    Ok(())
}

fn f64_sub(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Sub);
    Ok(())
}

fn f64_mul(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Mul);
    Ok(())
}

fn f64_div(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Div);
    Ok(())
}

fn f64_min(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Min);
    Ok(())
}

fn f64_max(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Max);
    Ok(())
}

fn f64_copysign(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64, ValType::F64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64Copysign);
    Ok(())
}

fn i32_wrap_i64(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32WrapI64);
    Ok(())
}

fn nontrapping_f32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.saturating_float_to_int_enabled && f32_on_stack(module, builder)
}

fn i32_trunc_f32_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    if module.config.disallow_traps {
        no_traps::trunc(Instruction::I32TruncF32S, builder, instructions);
    } else {
        instructions.push(Instruction::I32TruncF32S);
    }
    Ok(())
}

fn i32_trunc_f32_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    if module.config.disallow_traps {
        no_traps::trunc(Instruction::I32TruncF32U, builder, instructions);
    } else {
        instructions.push(Instruction::I32TruncF32U);
    }
    Ok(())
}

fn nontrapping_f64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.saturating_float_to_int_enabled && f64_on_stack(module, builder)
}

fn i32_trunc_f64_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    if module.config.disallow_traps {
        no_traps::trunc(Instruction::I32TruncF64S, builder, instructions);
    } else {
        instructions.push(Instruction::I32TruncF64S);
    }
    Ok(())
}

fn i32_trunc_f64_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    if module.config.disallow_traps {
        no_traps::trunc(Instruction::I32TruncF64U, builder, instructions);
    } else {
        instructions.push(Instruction::I32TruncF64U);
    }
    Ok(())
}

fn i64_extend_i32_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64ExtendI32S);
    Ok(())
}

fn i64_extend_i32_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64ExtendI32U);
    Ok(())
}

fn i64_trunc_f32_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::I64]);
    if module.config.disallow_traps {
        no_traps::trunc(Instruction::I64TruncF32S, builder, instructions);
    } else {
        instructions.push(Instruction::I64TruncF32S);
    }
    Ok(())
}

fn i64_trunc_f32_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::I64]);
    if module.config.disallow_traps {
        no_traps::trunc(Instruction::I64TruncF32U, builder, instructions);
    } else {
        instructions.push(Instruction::I64TruncF32U);
    }
    Ok(())
}

fn i64_trunc_f64_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::I64]);
    if module.config.disallow_traps {
        no_traps::trunc(Instruction::I64TruncF64S, builder, instructions);
    } else {
        instructions.push(Instruction::I64TruncF64S);
    }
    Ok(())
}

fn i64_trunc_f64_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::I64]);
    if module.config.disallow_traps {
        no_traps::trunc(Instruction::I64TruncF64U, builder, instructions);
    } else {
        instructions.push(Instruction::I64TruncF64U);
    }
    Ok(())
}

fn f32_convert_i32_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32ConvertI32S);
    Ok(())
}

fn f32_convert_i32_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32ConvertI32U);
    Ok(())
}

fn f32_convert_i64_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32ConvertI64S);
    Ok(())
}

fn f32_convert_i64_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32ConvertI64U);
    Ok(())
}

fn f32_demote_f64(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32DemoteF64);
    Ok(())
}

fn f64_convert_i32_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64ConvertI32S);
    Ok(())
}

fn f64_convert_i32_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64ConvertI32U);
    Ok(())
}

fn f64_convert_i64_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64ConvertI64S);
    Ok(())
}

fn f64_convert_i64_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64ConvertI64U);
    Ok(())
}

fn f64_promote_f32(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64PromoteF32);
    Ok(())
}

fn i32_reinterpret_f32(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32ReinterpretF32);
    Ok(())
}

fn i64_reinterpret_f64(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64ReinterpretF64);
    Ok(())
}

fn f32_reinterpret_i32(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::F32]);
    instructions.push(Instruction::F32ReinterpretI32);
    Ok(())
}

fn f64_reinterpret_i64(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::F64]);
    instructions.push(Instruction::F64ReinterpretI64);
    Ok(())
}

fn extendable_i32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.sign_extension_ops_enabled && i32_on_stack(module, builder)
}

fn i32_extend_8_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Extend8S);
    Ok(())
}

fn i32_extend_16_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32Extend16S);
    Ok(())
}

fn extendable_i64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.sign_extension_ops_enabled && i64_on_stack(module, builder)
}

fn i64_extend_8_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Extend8S);
    Ok(())
}

fn i64_extend_16_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Extend16S);
    Ok(())
}

fn i64_extend_32_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::I64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64Extend32S);
    Ok(())
}

fn i32_trunc_sat_f32_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32TruncSatF32S);
    Ok(())
}

fn i32_trunc_sat_f32_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32TruncSatF32U);
    Ok(())
}

fn i32_trunc_sat_f64_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32TruncSatF64S);
    Ok(())
}

fn i32_trunc_sat_f64_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::I32TruncSatF64U);
    Ok(())
}

fn i64_trunc_sat_f32_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64TruncSatF32S);
    Ok(())
}

fn i64_trunc_sat_f32_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F32]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64TruncSatF32U);
    Ok(())
}

fn i64_trunc_sat_f64_s(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64TruncSatF64S);
    Ok(())
}

fn i64_trunc_sat_f64_u(
    _: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::F64]);
    builder.push_operands(&[ValType::I64]);
    instructions.push(Instruction::I64TruncSatF64U);
    Ok(())
}

fn memory_offset(u: &mut Unstructured, module: &Module, memory_index: u32) -> Result<u64> {
    let MemoryOffsetChoices(a, b, c) = module.config.memory_offset_choices;
    assert!(a + b + c != 0);

    let memory_type = &module.memories[memory_index as usize];
    let min = memory_type
        .minimum
        .saturating_mul(crate::page_size(memory_type).into());
    let max = memory_type
        .maximum
        .map(|max| max.saturating_mul(crate::page_size(memory_type).into()))
        .unwrap_or(u64::MAX);

    let (min, max, true_max) = match (memory_type.memory64, module.config.disallow_traps) {
        (true, false) => {
            // 64-bit memories can use the limits calculated above as-is
            (min, max, u64::MAX)
        }
        (false, false) => {
            // 32-bit memories can't represent a full 4gb offset, so if that's the
            // min/max sizes then we need to switch the m to `u32::MAX`.
            (
                u64::from(u32::try_from(min).unwrap_or(u32::MAX)),
                u64::from(u32::try_from(max).unwrap_or(u32::MAX)),
                u64::from(u32::MAX),
            )
        }
        // The logic for non-trapping versions of load/store involves pushing
        // the offset + load/store size onto the stack as either an i32 or i64
        // value. So even though offsets can normally be as high as u32 or u64,
        // we need to limit them to lower in order for our non-trapping logic to
        // work. 16 is the number of bytes of the largest load type (V128).
        (true, true) => {
            let no_trap_max = (i64::MAX - 16) as u64;
            (min.min(no_trap_max), no_trap_max, no_trap_max)
        }
        (false, true) => {
            let no_trap_max = (i32::MAX - 16) as u64;
            (min.min(no_trap_max), no_trap_max, no_trap_max)
        }
    };

    let choice = u.int_in_range(0..=a + b + c - 1)?;
    if choice < a {
        u.int_in_range(0..=min)
    } else if choice < a + b {
        u.int_in_range(min..=max)
    } else {
        u.int_in_range(max..=true_max)
    }
}

fn mem_arg(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    alignments: &[u32],
) -> Result<MemArg> {
    let memory_index = if builder.type_on_stack(module, ValType::I32) {
        builder.pop_operands(module, &[ValType::I32]);
        memory_index(u, builder, ValType::I32)?
    } else {
        builder.pop_operands(module, &[ValType::I64]);
        memory_index(u, builder, ValType::I64)?
    };
    let offset = memory_offset(u, module, memory_index)?;
    let align = *u.choose(alignments)?;
    Ok(MemArg {
        memory_index,
        offset,
        align,
    })
}

fn memory_index(u: &mut Unstructured, builder: &CodeBuilder, ty: ValType) -> Result<u32> {
    if ty == ValType::I32 {
        Ok(*u.choose(&builder.allocs.memory32)?)
    } else {
        Ok(*u.choose(&builder.allocs.memory64)?)
    }
}

fn data_index(u: &mut Unstructured, module: &Module) -> Result<u32> {
    let data = module.data.len() as u32;
    assert!(data > 0);
    if data == 1 {
        Ok(0)
    } else {
        u.int_in_range(0..=data - 1)
    }
}

#[inline]
fn ref_null_valid(module: &Module, _: &mut CodeBuilder) -> bool {
    module.config.reference_types_enabled
}

fn ref_null(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let mut choices = vec![RefType::EXTERNREF, RefType::FUNCREF];
    if module.config.exceptions_enabled {
        choices.push(RefType::EXNREF);
    }
    if module.config.gc_enabled {
        let r = |heap_type| RefType {
            nullable: true,
            heap_type,
        };
        choices.push(r(HeapType::Any));
        choices.push(r(HeapType::Eq));
        choices.push(r(HeapType::Array));
        choices.push(r(HeapType::Struct));
        choices.push(r(HeapType::I31));
        choices.push(r(HeapType::None));
        choices.push(r(HeapType::NoFunc));
        choices.push(r(HeapType::NoExtern));
        for i in 0..module.types.len() {
            let i = u32::try_from(i).unwrap();
            choices.push(r(HeapType::Concrete(i)));
        }
    }
    let ty = *u.choose(&choices)?;
    builder.push_operand(Some(ty.into()));
    instructions.push(Instruction::RefNull(ty.heap_type));
    Ok(())
}

#[inline]
fn ref_func_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.reference_types_enabled && builder.allocs.referenced_functions.len() > 0
}

fn ref_func(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let i = *u.choose(&builder.allocs.referenced_functions)?;
    let ty = module.funcs[usize::try_from(i).unwrap()].0;
    builder.push_operand(Some(ValType::Ref(if module.config.gc_enabled {
        RefType {
            nullable: false,
            heap_type: HeapType::Concrete(ty),
        }
    } else {
        RefType::FUNCREF
    })));
    instructions.push(Instruction::RefFunc(i));
    Ok(())
}

#[inline]
fn ref_as_non_null_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled && builder.ref_type_on_stack().is_some()
}

fn ref_as_non_null(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let ref_ty = match builder.pop_ref_type() {
        Some(r) => r,
        None => module.arbitrary_ref_type(u)?,
    };
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable: false,
        heap_type: ref_ty.heap_type,
    })));
    instructions.push(Instruction::RefAsNonNull);
    Ok(())
}

#[inline]
fn ref_eq_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    let eq_ref = ValType::Ref(RefType {
        nullable: true,
        heap_type: HeapType::Eq,
    });
    module.config.gc_enabled && builder.types_on_stack(module, &[eq_ref, eq_ref])
}

fn ref_eq(
    _u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    builder.pop_operand();
    builder.push_operand(Some(ValType::I32));
    instructions.push(Instruction::RefEq);
    Ok(())
}

#[inline]
fn ref_test_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled && builder.ref_type_on_stack().is_some()
}

fn ref_test(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let ref_ty = match builder.pop_ref_type() {
        Some(r) => r,
        None => module.arbitrary_ref_type(u)?,
    };
    builder.push_operand(Some(ValType::I32));

    let sub_ty = module.arbitrary_matching_heap_type(u, ref_ty.heap_type)?;
    instructions.push(if !ref_ty.nullable || u.arbitrary()? {
        Instruction::RefTestNonNull(sub_ty)
    } else {
        Instruction::RefTestNullable(sub_ty)
    });
    Ok(())
}

#[inline]
fn ref_cast_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.gc_enabled
        && builder.ref_type_on_stack().is_some()
}

fn ref_cast(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let ref_ty = match builder.pop_ref_type() {
        Some(r) => r,
        None => module.arbitrary_ref_type(u)?,
    };
    let sub_ty = RefType {
        nullable: if !ref_ty.nullable {
            false
        } else {
            u.arbitrary()?
        },
        heap_type: module.arbitrary_matching_heap_type(u, ref_ty.heap_type)?,
    };
    builder.push_operand(Some(ValType::Ref(sub_ty)));

    instructions.push(if !sub_ty.nullable {
        Instruction::RefCastNonNull(sub_ty.heap_type)
    } else {
        Instruction::RefCastNullable(sub_ty.heap_type)
    });
    Ok(())
}

#[inline]
fn ref_is_null_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.reference_types_enabled
        && (builder.type_on_stack(module, ValType::EXTERNREF)
            || builder.type_on_stack(module, ValType::FUNCREF))
}

fn ref_is_null(
    _: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_ref_type();
    builder.push_operands(&[ValType::I32]);
    instructions.push(Instruction::RefIsNull);
    Ok(())
}

#[inline]
fn table_fill_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.reference_types_enabled
        && module.config.bulk_memory_enabled
        && !module.config.disallow_traps // Non-trapping table fill generation not yet implemented
        && table_fill_candidates(module, builder).next().is_some()
}

fn table_fill_candidates<'a>(
    module: &'a Module,
    builder: &'a CodeBuilder,
) -> impl Iterator<Item = u32> + 'a {
    module
        .tables
        .iter()
        .enumerate()
        .filter(move |(_, t)| {
            builder.types_on_stack(
                module,
                &[t.index_type(), t.element_type.into(), t.index_type()],
            )
        })
        .map(|(i, _)| i as u32)
}

fn table_fill(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let table = *u.choose(&table_fill_candidates(module, builder).collect::<Vec<_>>())?;
    let ty = &module.tables[table as usize];
    builder.pop_operands(
        module,
        &[ty.index_type(), ty.element_type.into(), ty.index_type()],
    );
    instructions.push(Instruction::TableFill(table));
    Ok(())
}

#[inline]
fn table_set_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.reference_types_enabled
    && !module.config.disallow_traps // Non-trapping table.set generation not yet implemented
    && table_set_candidates(module, builder).next().is_some()
}

fn table_set_candidates<'a>(
    module: &'a Module,
    builder: &'a CodeBuilder,
) -> impl Iterator<Item = u32> + 'a {
    module
        .tables
        .iter()
        .enumerate()
        .filter(move |(_, t)| {
            builder.types_on_stack(module, &[t.index_type(), t.element_type.into()])
        })
        .map(|(i, _)| i as u32)
}

fn table_set(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let table = *u.choose(&table_set_candidates(module, builder).collect::<Vec<_>>())?;
    let ty = &module.tables[table as usize];
    builder.pop_operands(module, &[ty.index_type(), ty.element_type.into()]);
    instructions.push(Instruction::TableSet(table));
    Ok(())
}

#[inline]
fn table_get_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.reference_types_enabled {
        return false;
    }
    // Non-trapping table.get generation not yet implemented
    if module.config.disallow_traps {
        return false;
    }
    if builder.type_on_stack(module, ValType::I32) && builder.allocs.table32.len() > 0 {
        return true;
    }
    if builder.type_on_stack(module, ValType::I64) && builder.allocs.table64.len() > 0 {
        return true;
    }
    false
}

fn table_get(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let candidates = if builder.type_on_stack(module, ValType::I32) {
        builder.pop_operands(module, &[ValType::I32]);
        &builder.allocs.table32
    } else {
        builder.pop_operands(module, &[ValType::I64]);
        &builder.allocs.table64
    };
    let idx = *u.choose(candidates)?;
    let ty = module.tables[idx as usize].element_type;
    builder.push_operands(&[ty.into()]);
    instructions.push(Instruction::TableGet(idx as u32));
    Ok(())
}

#[inline]
fn table_size_valid(module: &Module, _: &mut CodeBuilder) -> bool {
    module.config.reference_types_enabled && module.tables.len() > 0
}

fn table_size(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let table = u.int_in_range(0..=module.tables.len() - 1)?;
    let ty = &module.tables[table];
    builder.push_operands(&[ty.index_type()]);
    instructions.push(Instruction::TableSize(table as u32));
    Ok(())
}

#[inline]
fn table_grow_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.reference_types_enabled && table_grow_candidates(module, builder).next().is_some()
}

fn table_grow_candidates<'a>(
    module: &'a Module,
    builder: &'a CodeBuilder,
) -> impl Iterator<Item = u32> + 'a {
    module
        .tables
        .iter()
        .enumerate()
        .filter(move |(_, t)| {
            builder.types_on_stack(module, &[t.element_type.into(), t.index_type()])
        })
        .map(|(i, _)| i as u32)
}

fn table_grow(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let table = *u.choose(&table_grow_candidates(module, builder).collect::<Vec<_>>())?;
    let ty = &module.tables[table as usize];
    builder.pop_operands(module, &[ty.element_type.into(), ty.index_type()]);
    builder.push_operands(&[ty.index_type()]);
    instructions.push(Instruction::TableGrow(table));
    Ok(())
}

#[inline]
fn table_copy_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.bulk_memory_enabled {
        return false;
    }
    // Non-trapping table.copy generation not yet implemented
    if module.config.disallow_traps {
        return false;
    }
    if builder.types_on_stack(module, &[ValType::I64, ValType::I64, ValType::I64]) {
        return builder.allocs.table_copy_64_to_64.len() > 0;
    }
    if builder.types_on_stack(module, &[ValType::I32, ValType::I32, ValType::I32]) {
        return builder.allocs.table_copy_32_to_32.len() > 0;
    }
    if builder.types_on_stack(module, &[ValType::I64, ValType::I32, ValType::I32]) {
        return builder.allocs.table_copy_32_to_64.len() > 0;
    }
    if builder.types_on_stack(module, &[ValType::I32, ValType::I64, ValType::I32]) {
        return builder.allocs.table_copy_64_to_32.len() > 0;
    }
    false
}

fn table_copy(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    use CopyIndexSize::*;

    let (src_table, dst_table) = match gen_copy_src_and_dst(module, builder) {
        (I32, I32) => *u.choose(&builder.allocs.table_copy_32_to_32)?,
        (I32, I64) => *u.choose(&builder.allocs.table_copy_32_to_64)?,
        (I64, I32) => *u.choose(&builder.allocs.table_copy_64_to_32)?,
        (I64, I64) => *u.choose(&builder.allocs.table_copy_64_to_64)?,
    };
    instructions.push(Instruction::TableCopy {
        src_table,
        dst_table,
    });
    Ok(())
}

#[inline]
fn table_init_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.bulk_memory_enabled {
        return false;
    }
    // Non-trapping table.init generation not yet implemented.
    if module.config.disallow_traps {
        return false;
    }
    if builder.allocs.table32_init.len() > 0
        && builder.types_on_stack(module, &[ValType::I32, ValType::I32, ValType::I32])
    {
        return true;
    }
    if builder.allocs.table64_init.len() > 0
        && builder.types_on_stack(module, &[ValType::I64, ValType::I32, ValType::I32])
    {
        return true;
    }
    false
}

fn table_init(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let candidates = if builder.types_on_stack(module, &[ValType::I64, ValType::I32, ValType::I32])
    {
        builder.pop_operands(module, &[ValType::I64, ValType::I32, ValType::I32]);
        &builder.allocs.table64_init
    } else {
        builder.pop_operands(module, &[ValType::I32, ValType::I32, ValType::I32]);
        &builder.allocs.table32_init
    };
    let (elem_index, table) = *u.choose(&candidates)?;
    instructions.push(Instruction::TableInit { elem_index, table });
    Ok(())
}

#[inline]
fn elem_drop_valid(module: &Module, _builder: &mut CodeBuilder) -> bool {
    module.config.bulk_memory_enabled && module.elems.len() > 0
}

fn elem_drop(
    u: &mut Unstructured,
    module: &Module,
    _builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let segment = u.int_in_range(0..=module.elems.len() - 1)? as u32;
    instructions.push(Instruction::ElemDrop(segment));
    Ok(())
}

#[inline]
fn struct_new_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && module
            .struct_types
            .iter()
            .copied()
            .any(|i| builder.field_types_on_stack(module, &module.ty(i).unwrap_struct().fields))
}

fn struct_new(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = module
        .struct_types
        .iter()
        .filter(|i| builder.field_types_on_stack(module, &module.ty(**i).unwrap_struct().fields))
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let ty = module
        .struct_types
        .iter()
        .copied()
        .filter(|i| builder.field_types_on_stack(module, &module.ty(*i).unwrap_struct().fields))
        .nth(i)
        .unwrap();

    for _ in module.ty(ty).unwrap_struct().fields.iter() {
        builder.pop_operand();
    }
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable: false,
        heap_type: HeapType::Concrete(ty),
    })));

    instructions.push(Instruction::StructNew(ty));
    Ok(())
}

#[inline]
fn struct_new_default_valid(module: &Module, _builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && module.struct_types.iter().copied().any(|i| {
            module
                .ty(i)
                .unwrap_struct()
                .fields
                .iter()
                .all(|f| f.element_type.is_defaultable())
        })
}

fn struct_new_default(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = module
        .struct_types
        .iter()
        .filter(|i| {
            module
                .ty(**i)
                .unwrap_struct()
                .fields
                .iter()
                .all(|f| f.element_type.is_defaultable())
        })
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let ty = module
        .struct_types
        .iter()
        .copied()
        .filter(|i| {
            module
                .ty(*i)
                .unwrap_struct()
                .fields
                .iter()
                .all(|f| f.element_type.is_defaultable())
        })
        .nth(i)
        .unwrap();

    builder.push_operand(Some(ValType::Ref(RefType {
        nullable: false,
        heap_type: HeapType::Concrete(ty),
    })));

    instructions.push(Instruction::StructNewDefault(ty));
    Ok(())
}

#[inline]
fn struct_get_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && !module.config.disallow_traps
        && builder.non_empty_struct_ref_on_stack(module, !module.config.disallow_traps)
}

fn struct_get(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let (_, struct_type_index) = builder.pop_concrete_ref_type();
    let struct_ty = module.ty(struct_type_index).unwrap_struct();
    let num_fields = u32::try_from(struct_ty.fields.len()).unwrap();
    debug_assert!(num_fields > 0);
    let field_index = u.int_in_range(0..=num_fields - 1)?;
    let (val_ty, ext) = match struct_ty.fields[usize::try_from(field_index).unwrap()].element_type {
        StorageType::I8 | StorageType::I16 => (ValType::I32, Some(u.arbitrary()?)),
        StorageType::Val(v) => (v, None),
    };
    builder.push_operand(Some(val_ty));
    instructions.push(match ext {
        None => Instruction::StructGet {
            struct_type_index,
            field_index,
        },
        Some(true) => Instruction::StructGetS {
            struct_type_index,
            field_index,
        },
        Some(false) => Instruction::StructGetU {
            struct_type_index,
            field_index,
        },
    });
    Ok(())
}

#[inline]
fn struct_set_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.gc_enabled {
        return false;
    }
    match builder.concrete_struct_ref_type_on_stack_at(module, 1) {
        None => return false,
        Some((true, _, _)) if module.config.disallow_traps => return false,
        Some((_, _, ty)) => ty
            .fields
            .iter()
            .any(|f| f.mutable && builder.type_on_stack(module, f.element_type.unpack())),
    }
}

fn struct_set(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let val_ty = builder.pop_operand();
    let (_, struct_type_index) = builder.pop_concrete_ref_type();
    let struct_ty = module.ty(struct_type_index).unwrap_struct();

    let valid_field = |f: &FieldType| -> bool {
        match val_ty {
            None => f.mutable,
            Some(val_ty) => {
                f.mutable && module.val_type_is_sub_type(val_ty, f.element_type.unpack())
            }
        }
    };

    let n = struct_ty.fields.iter().filter(|f| valid_field(f)).count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let (field_index, _) = struct_ty
        .fields
        .iter()
        .enumerate()
        .filter(|(_, f)| valid_field(f))
        .nth(i)
        .unwrap();
    let field_index = u32::try_from(field_index).unwrap();

    instructions.push(Instruction::StructSet {
        struct_type_index,
        field_index,
    });
    Ok(())
}

#[inline]
fn array_new_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && builder.type_on_stack(module, ValType::I32)
        && module
            .array_types
            .iter()
            .any(|i| builder.field_type_on_stack_at(module, 1, module.ty(*i).unwrap_array().0))
}

fn array_new(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = module
        .array_types
        .iter()
        .filter(|i| builder.field_type_on_stack_at(module, 1, module.ty(**i).unwrap_array().0))
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let ty = module
        .array_types
        .iter()
        .copied()
        .filter(|i| builder.field_type_on_stack_at(module, 1, module.ty(*i).unwrap_array().0))
        .nth(i)
        .unwrap();

    builder.pop_operand();
    builder.pop_operand();
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable: false,
        heap_type: HeapType::Concrete(ty),
    })));

    instructions.push(Instruction::ArrayNew(ty));
    Ok(())
}

#[inline]
fn array_new_fixed_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && module
            .array_types
            .iter()
            .any(|i| builder.field_type_on_stack(module, module.ty(*i).unwrap_array().0))
}

fn array_new_fixed(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = module
        .array_types
        .iter()
        .filter(|i| builder.field_type_on_stack(module, module.ty(**i).unwrap_array().0))
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let array_type_index = module
        .array_types
        .iter()
        .copied()
        .filter(|i| builder.field_type_on_stack(module, module.ty(*i).unwrap_array().0))
        .nth(i)
        .unwrap();
    let elem_ty = module
        .ty(array_type_index)
        .unwrap_array()
        .0
        .element_type
        .unpack();

    let m = (0..builder.operands().len())
        .take_while(|i| builder.type_on_stack_at(module, *i, elem_ty))
        .count();
    debug_assert!(m > 0);
    let array_size = u.int_in_range(0..=m - 1)?;
    let array_size = u32::try_from(array_size).unwrap();

    for _ in 0..array_size {
        builder.pop_operand();
    }
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable: false,
        heap_type: HeapType::Concrete(array_type_index),
    })));

    instructions.push(Instruction::ArrayNewFixed {
        array_type_index,
        array_size,
    });
    Ok(())
}

#[inline]
fn array_new_default_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && builder.type_on_stack(module, ValType::I32)
        && module
            .array_types
            .iter()
            .any(|i| module.ty(*i).unwrap_array().0.element_type.is_defaultable())
}

fn array_new_default(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = module
        .array_types
        .iter()
        .filter(|i| {
            module
                .ty(**i)
                .unwrap_array()
                .0
                .element_type
                .is_defaultable()
        })
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let array_type_index = module
        .array_types
        .iter()
        .copied()
        .filter(|i| module.ty(*i).unwrap_array().0.element_type.is_defaultable())
        .nth(i)
        .unwrap();

    builder.pop_operand();
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable: false,
        heap_type: HeapType::Concrete(array_type_index),
    })));
    instructions.push(Instruction::ArrayNewDefault(array_type_index));
    Ok(())
}

#[inline]
fn array_new_data_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && module.config.bulk_memory_enabled // Requires data count section
        && !module.config.disallow_traps
        && !module.data.is_empty()
        && builder.types_on_stack(module, &[ValType::I32, ValType::I32])
        && module.array_types.iter().any(|i| {
            let ty = module.ty(*i).unwrap_array().0.element_type.unpack();
            ty.is_numeric() | ty.is_vector()
        })
}

fn array_new_data(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = module
        .array_types
        .iter()
        .filter(|i| {
            let ty = module.ty(**i).unwrap_array().0.element_type.unpack();
            ty.is_numeric() | ty.is_vector()
        })
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let array_type_index = module
        .array_types
        .iter()
        .copied()
        .filter(|i| {
            let ty = module.ty(*i).unwrap_array().0.element_type.unpack();
            ty.is_numeric() | ty.is_vector()
        })
        .nth(i)
        .unwrap();

    let m = module.data.len();
    debug_assert!(m > 0);
    let array_data_index = u.int_in_range(0..=m - 1)?;
    let array_data_index = u32::try_from(array_data_index).unwrap();

    builder.pop_operand();
    builder.pop_operand();
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable: false,
        heap_type: HeapType::Concrete(array_type_index),
    })));
    instructions.push(Instruction::ArrayNewData {
        array_type_index,
        array_data_index,
    });
    Ok(())
}

fn module_has_elem_segment_of_array_type(module: &Module, ty: &ArrayType) -> bool {
    module
        .elems
        .iter()
        .any(|elem| module.val_type_is_sub_type(ValType::Ref(elem.ty), ty.0.element_type.unpack()))
}

#[inline]
fn array_new_elem_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && !module.config.disallow_traps
        && builder.types_on_stack(module, &[ValType::I32, ValType::I32])
        && module
            .array_types
            .iter()
            .any(|i| module_has_elem_segment_of_array_type(module, module.ty(*i).unwrap_array()))
}

fn array_new_elem(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let n = module
        .array_types
        .iter()
        .filter(|i| module_has_elem_segment_of_array_type(module, module.ty(**i).unwrap_array()))
        .count();
    debug_assert!(n > 0);
    let i = u.int_in_range(0..=n - 1)?;
    let array_type_index = module
        .array_types
        .iter()
        .copied()
        .filter(|i| module_has_elem_segment_of_array_type(module, module.ty(*i).unwrap_array()))
        .nth(i)
        .unwrap();
    let elem_ty = module
        .ty(array_type_index)
        .unwrap_array()
        .0
        .element_type
        .unpack();

    let m = module
        .elems
        .iter()
        .filter(|elem| module.val_type_is_sub_type(ValType::Ref(elem.ty), elem_ty))
        .count();
    debug_assert!(m > 0);
    let j = u.int_in_range(0..=m - 1)?;
    let (array_elem_index, _) = module
        .elems
        .iter()
        .enumerate()
        .filter(|(_, elem)| module.val_type_is_sub_type(ValType::Ref(elem.ty), elem_ty))
        .nth(j)
        .unwrap();
    let array_elem_index = u32::try_from(array_elem_index).unwrap();

    builder.pop_operand();
    builder.pop_operand();
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable: false,
        heap_type: HeapType::Concrete(array_type_index),
    })));

    instructions.push(Instruction::ArrayNewElem {
        array_type_index,
        array_elem_index,
    });
    Ok(())
}

#[inline]
fn array_get_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && !module.config.disallow_traps // TODO: add support for disallowing traps
        && builder.type_on_stack(module, ValType::I32)
        && builder.concrete_array_ref_type_on_stack_at(module, 1).is_some()
}

fn array_get(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    let (_, array_type_index) = builder.pop_concrete_ref_type();
    let elem_ty = module.ty(array_type_index).unwrap_array().0.element_type;
    builder.push_operand(Some(elem_ty.unpack()));
    instructions.push(match elem_ty {
        StorageType::I8 | StorageType::I16 => {
            if u.arbitrary()? {
                Instruction::ArrayGetS(array_type_index)
            } else {
                Instruction::ArrayGetU(array_type_index)
            }
        }
        StorageType::Val(_) => Instruction::ArrayGet(array_type_index),
    });
    Ok(())
}

#[inline]
fn array_set_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.gc_enabled
        // TODO: implement disallowing traps.
        || module.config.disallow_traps
        || !builder.type_on_stack_at(module, 1, ValType::I32)
    {
        return false;
    }
    match builder.concrete_array_ref_type_on_stack_at(module, 2) {
        None => false,
        Some((_nullable, _idx, array_ty)) => {
            array_ty.0.mutable && builder.field_type_on_stack(module, array_ty.0)
        }
    }
}

fn array_set(
    _u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    builder.pop_operand();
    let (_, ty) = builder.pop_concrete_ref_type();
    instructions.push(Instruction::ArraySet(ty));
    Ok(())
}

#[inline]
fn array_len_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && builder.type_on_stack(
            module,
            ValType::Ref(RefType {
                nullable: true,
                heap_type: HeapType::Array,
            }),
        )
}

fn array_len(
    _u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    builder.push_operand(Some(ValType::I32));
    instructions.push(Instruction::ArrayLen);
    Ok(())
}

#[inline]
fn array_fill_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.gc_enabled
        // TODO: add support for disallowing traps
        || module.config.disallow_traps
        || !builder.type_on_stack_at(module, 0, ValType::I32)
        || !builder.type_on_stack_at(module, 2, ValType::I32)
    {
        return false;
    }
    match builder.concrete_array_ref_type_on_stack_at(module, 3) {
        None => return false,
        Some((_, _, array_ty)) => {
            array_ty.0.mutable && builder.field_type_on_stack_at(module, 1, array_ty.0)
        }
    }
}

fn array_fill(
    _u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    builder.pop_operand();
    builder.pop_operand();
    let (_, ty) = builder.pop_concrete_ref_type();
    instructions.push(Instruction::ArrayFill(ty));
    Ok(())
}

#[inline]
fn array_copy_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.gc_enabled
        // TODO: add support for disallowing traps
        || module.config.disallow_traps
        || !builder.type_on_stack_at(module, 0, ValType::I32)
        || !builder.type_on_stack_at(module, 1, ValType::I32)
        || !builder.type_on_stack_at(module, 3, ValType::I32)
    {
        return false;
    }
    let x = match builder.concrete_array_ref_type_on_stack_at(module, 4) {
        None => return false,
        Some((_, _, x)) => x,
    };
    if !x.0.mutable {
        return false;
    }
    let y = match builder.concrete_array_ref_type_on_stack_at(module, 2) {
        None => return false,
        Some((_, _, y)) => y,
    };
    match (x.0.element_type, y.0.element_type) {
        (StorageType::I8, StorageType::I8) => true,
        (StorageType::I8, _) => false,
        (StorageType::I16, StorageType::I16) => true,
        (StorageType::I16, _) => false,
        (StorageType::Val(x), StorageType::Val(y)) => module.val_type_is_sub_type(y, x),
        (StorageType::Val(_), _) => false,
    }
}

fn array_copy(
    _u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    builder.pop_operand();
    let (_, array_type_index_src) = builder.pop_concrete_ref_type();
    builder.pop_operand();
    let (_, array_type_index_dst) = builder.pop_concrete_ref_type();
    instructions.push(Instruction::ArrayCopy {
        array_type_index_dst,
        array_type_index_src,
    });
    Ok(())
}

#[inline]
fn array_init_data_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.gc_enabled
        || !module.config.bulk_memory_enabled // Requires data count section
        || module.config.disallow_traps
        || module.data.is_empty()
        || !builder.types_on_stack(module, &[ValType::I32, ValType::I32, ValType::I32])
    {
        return false;
    }
    match builder.concrete_array_ref_type_on_stack_at(module, 3) {
        None => return false,
        Some((_, _, ty)) => {
            let elem_ty = ty.0.element_type.unpack();
            ty.0.mutable && (elem_ty.is_numeric() || elem_ty.is_vector())
        }
    }
}

fn array_init_data(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    builder.pop_operand();
    builder.pop_operand();
    let (_, array_type_index) = builder.pop_concrete_ref_type();

    let n = module.data.len();
    debug_assert!(n > 0);
    let array_data_index = u.int_in_range(0..=n - 1)?;
    let array_data_index = u32::try_from(array_data_index).unwrap();

    instructions.push(Instruction::ArrayInitData {
        array_type_index,
        array_data_index,
    });
    Ok(())
}

#[inline]
fn array_init_elem_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    if !module.config.gc_enabled
        || module.config.disallow_traps
        || !builder.types_on_stack(module, &[ValType::I32, ValType::I32, ValType::I32])
    {
        return false;
    }
    match builder.concrete_array_ref_type_on_stack_at(module, 3) {
        None => return false,
        Some((_, _, array_ty)) => {
            array_ty.0.mutable && module_has_elem_segment_of_array_type(module, &array_ty)
        }
    }
}

fn array_init_elem(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    builder.pop_operand();
    builder.pop_operand();
    let (_, array_type_index) = builder.pop_concrete_ref_type();

    let elem_ty = module
        .ty(array_type_index)
        .unwrap_array()
        .0
        .element_type
        .unpack();

    let n = module
        .elems
        .iter()
        .filter(|elem| module.val_type_is_sub_type(ValType::Ref(elem.ty), elem_ty))
        .count();
    debug_assert!(n > 0);
    let j = u.int_in_range(0..=n - 1)?;
    let (array_elem_index, _) = module
        .elems
        .iter()
        .enumerate()
        .filter(|(_, elem)| module.val_type_is_sub_type(ValType::Ref(elem.ty), elem_ty))
        .nth(j)
        .unwrap();
    let array_elem_index = u32::try_from(array_elem_index).unwrap();

    instructions.push(Instruction::ArrayInitElem {
        array_type_index,
        array_elem_index,
    });
    Ok(())
}

#[inline]
fn ref_i31_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled && builder.type_on_stack(module, ValType::I32)
}

fn ref_i31(
    _u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable: false,
        heap_type: HeapType::I31,
    })));
    instructions.push(Instruction::RefI31);
    Ok(())
}

#[inline]
fn i31_get_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && builder.type_on_stack(
            module,
            ValType::Ref(RefType {
                nullable: true,
                heap_type: HeapType::I31,
            }),
        )
}

fn i31_get(
    u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operand();
    builder.push_operand(Some(ValType::I32));
    instructions.push(if u.arbitrary()? {
        Instruction::I31GetS
    } else {
        Instruction::I31GetU
    });
    Ok(())
}

#[inline]
fn any_convert_extern_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && builder.type_on_stack(
            module,
            ValType::Ref(RefType {
                nullable: true,
                heap_type: HeapType::Extern,
            }),
        )
}

fn any_convert_extern(
    u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let nullable = match builder.pop_ref_type() {
        None => u.arbitrary()?,
        Some(r) => r.nullable,
    };
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable,
        heap_type: HeapType::Any,
    })));
    instructions.push(Instruction::AnyConvertExtern);
    Ok(())
}

#[inline]
fn extern_convert_any_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    module.config.gc_enabled
        && builder.type_on_stack(
            module,
            ValType::Ref(RefType {
                nullable: true,
                heap_type: HeapType::Any,
            }),
        )
}

fn extern_convert_any(
    u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    let nullable = match builder.pop_ref_type() {
        None => u.arbitrary()?,
        Some(r) => r.nullable,
    };
    builder.push_operand(Some(ValType::Ref(RefType {
        nullable,
        heap_type: HeapType::Extern,
    })));
    instructions.push(Instruction::ExternConvertAny);
    Ok(())
}

fn lane_index(u: &mut Unstructured, number_of_lanes: u8) -> Result<u8> {
    u.int_in_range(0..=(number_of_lanes - 1))
}

#[inline]
fn simd_v128_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.types_on_stack(module, &[ValType::V128])
}

#[inline]
fn simd_v128_on_stack_relaxed(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.relaxed_simd_enabled
        && builder.types_on_stack(module, &[ValType::V128])
}

#[inline]
fn simd_v128_v128_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.types_on_stack(module, &[ValType::V128, ValType::V128])
}

#[inline]
fn simd_v128_v128_on_stack_relaxed(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.relaxed_simd_enabled
        && builder.types_on_stack(module, &[ValType::V128, ValType::V128])
}

#[inline]
fn simd_v128_v128_v128_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.types_on_stack(module, &[ValType::V128, ValType::V128, ValType::V128])
}

#[inline]
fn simd_v128_v128_v128_on_stack_relaxed(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.relaxed_simd_enabled
        && builder.types_on_stack(module, &[ValType::V128, ValType::V128, ValType::V128])
}

#[inline]
fn simd_v128_i32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.types_on_stack(module, &[ValType::V128, ValType::I32])
}

#[inline]
fn simd_v128_i64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.types_on_stack(module, &[ValType::V128, ValType::I64])
}

#[inline]
fn simd_v128_f32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.types_on_stack(module, &[ValType::V128, ValType::F32])
}

#[inline]
fn simd_v128_f64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.types_on_stack(module, &[ValType::V128, ValType::F64])
}

#[inline]
fn simd_i32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.type_on_stack(module, ValType::I32)
}

#[inline]
fn simd_i64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.type_on_stack(module, ValType::I64)
}

#[inline]
fn simd_f32_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.type_on_stack(module, ValType::F32)
}

#[inline]
fn simd_f64_on_stack(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && builder.type_on_stack(module, ValType::F64)
}

#[inline]
fn simd_have_memory_and_offset(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && have_memory_and_offset(module, builder)
}

#[inline]
fn simd_have_memory_and_offset_and_v128(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && store_valid(module, builder, || ValType::V128)
}

#[inline]
fn simd_load_lane_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    // The SIMD non-trapping case is not yet implemented.
    !module.config.disallow_traps && simd_have_memory_and_offset_and_v128(module, builder)
}

#[inline]
fn simd_v128_store_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    !module.config.disallow_traps
        && module.config.simd_enabled
        && store_valid(module, builder, || ValType::V128)
}

#[inline]
fn simd_store_lane_valid(module: &Module, builder: &mut CodeBuilder) -> bool {
    // The SIMD non-trapping case is not yet implemented.
    !module.config.disallow_traps && simd_v128_store_valid(module, builder)
}

#[inline]
fn simd_enabled(module: &Module, _: &mut CodeBuilder) -> bool {
    module.config.simd_enabled
}

macro_rules! simd_load {
    ($instruction:ident, $generator_fn_name:ident, $alignments:expr) => {
        fn $generator_fn_name(
            u: &mut Unstructured,
            module: &Module,
            builder: &mut CodeBuilder,

            instructions: &mut Vec<Instruction>,
        ) -> Result<()> {
            let memarg = mem_arg(u, module, builder, $alignments)?;
            builder.push_operands(&[ValType::V128]);
            if module.config.disallow_traps {
                no_traps::load(
                    Instruction::$instruction(memarg),
                    module,
                    builder,
                    instructions,
                );
            } else {
                instructions.push(Instruction::$instruction(memarg));
            }
            Ok(())
        }
    };
}

simd_load!(V128Load, v128_load, &[0, 1, 2, 3, 4]);
simd_load!(V128Load8x8S, v128_load8x8s, &[0, 1, 2, 3]);
simd_load!(V128Load8x8U, v128_load8x8u, &[0, 1, 2, 3]);
simd_load!(V128Load16x4S, v128_load16x4s, &[0, 1, 2, 3]);
simd_load!(V128Load16x4U, v128_load16x4u, &[0, 1, 2, 3]);
simd_load!(V128Load32x2S, v128_load32x2s, &[0, 1, 2, 3]);
simd_load!(V128Load32x2U, v128_load32x2u, &[0, 1, 2, 3]);
simd_load!(V128Load8Splat, v128_load8_splat, &[0]);
simd_load!(V128Load16Splat, v128_load16_splat, &[0, 1]);
simd_load!(V128Load32Splat, v128_load32_splat, &[0, 1, 2]);
simd_load!(V128Load64Splat, v128_load64_splat, &[0, 1, 2, 3]);
simd_load!(V128Load32Zero, v128_load32_zero, &[0, 1, 2]);
simd_load!(V128Load64Zero, v128_load64_zero, &[0, 1, 2, 3]);

fn v128_store(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::V128]);
    let memarg = mem_arg(u, module, builder, &[0, 1, 2, 3, 4])?;
    if module.config.disallow_traps {
        no_traps::store(
            Instruction::V128Store(memarg),
            module,
            builder,
            instructions,
        );
    } else {
        instructions.push(Instruction::V128Store(memarg));
    }
    Ok(())
}

macro_rules! simd_load_lane {
    ($instruction:ident, $generator_fn_name:ident, $alignments:expr, $number_of_lanes:expr) => {
        fn $generator_fn_name(
            u: &mut Unstructured,
            module: &Module,
            builder: &mut CodeBuilder,
            instructions: &mut Vec<Instruction>,
        ) -> Result<()> {
            builder.pop_operands(module, &[ValType::V128]);
            let memarg = mem_arg(u, module, builder, $alignments)?;
            builder.push_operands(&[ValType::V128]);
            instructions.push(Instruction::$instruction {
                memarg,
                lane: lane_index(u, $number_of_lanes)?,
            });
            Ok(())
        }
    };
}

simd_load_lane!(V128Load8Lane, v128_load8_lane, &[0], 16);
simd_load_lane!(V128Load16Lane, v128_load16_lane, &[0, 1], 8);
simd_load_lane!(V128Load32Lane, v128_load32_lane, &[0, 1, 2], 4);
simd_load_lane!(V128Load64Lane, v128_load64_lane, &[0, 1, 2, 3], 2);

macro_rules! simd_store_lane {
    ($instruction:ident, $generator_fn_name:ident, $alignments:expr, $number_of_lanes:expr) => {
        fn $generator_fn_name(
            u: &mut Unstructured,
            module: &Module,
            builder: &mut CodeBuilder,
            instructions: &mut Vec<Instruction>,
        ) -> Result<()> {
            builder.pop_operands(module, &[ValType::V128]);
            let memarg = mem_arg(u, module, builder, $alignments)?;
            instructions.push(Instruction::$instruction {
                memarg,
                lane: lane_index(u, $number_of_lanes)?,
            });
            Ok(())
        }
    };
}

simd_store_lane!(V128Store8Lane, v128_store8_lane, &[0], 16);
simd_store_lane!(V128Store16Lane, v128_store16_lane, &[0, 1], 8);
simd_store_lane!(V128Store32Lane, v128_store32_lane, &[0, 1, 2], 4);
simd_store_lane!(V128Store64Lane, v128_store64_lane, &[0, 1, 2, 3], 2);

fn v128_const(
    u: &mut Unstructured,
    _module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.push_operands(&[ValType::V128]);
    let c = i128::from_le_bytes(u.arbitrary()?);
    instructions.push(Instruction::V128Const(c));
    Ok(())
}

fn i8x16_shuffle(
    u: &mut Unstructured,
    module: &Module,
    builder: &mut CodeBuilder,
    instructions: &mut Vec<Instruction>,
) -> Result<()> {
    builder.pop_operands(module, &[ValType::V128, ValType::V128]);
    builder.push_operands(&[ValType::V128]);
    let mut lanes = [0; 16];
    for i in 0..16 {
        lanes[i] = u.int_in_range(0..=31)?;
    }
    instructions.push(Instruction::I8x16Shuffle(lanes));
    Ok(())
}

macro_rules! simd_lane_access {
    ($instruction:ident, $generator_fn_name:ident, $in_types:expr => $out_types:expr, $number_of_lanes:expr) => {
        fn $generator_fn_name(
            u: &mut Unstructured,
            module: &Module,
            builder: &mut CodeBuilder,
            instructions: &mut Vec<Instruction>,
        ) -> Result<()> {
            builder.pop_operands(module, $in_types);
            builder.push_operands($out_types);
            instructions.push(Instruction::$instruction(lane_index(u, $number_of_lanes)?));
            Ok(())
        }
    };
}

simd_lane_access!(I8x16ExtractLaneS, i8x16_extract_lane_s, &[ValType::V128] => &[ValType::I32], 16);
simd_lane_access!(I8x16ExtractLaneU, i8x16_extract_lane_u, &[ValType::V128] => &[ValType::I32], 16);
simd_lane_access!(I8x16ReplaceLane, i8x16_replace_lane, &[ValType::V128, ValType::I32] => &[ValType::V128], 16);
simd_lane_access!(I16x8ExtractLaneS, i16x8_extract_lane_s, &[ValType::V128] => &[ValType::I32], 8);
simd_lane_access!(I16x8ExtractLaneU, i16x8_extract_lane_u, &[ValType::V128] => &[ValType::I32], 8);
simd_lane_access!(I16x8ReplaceLane, i16x8_replace_lane, &[ValType::V128, ValType::I32] => &[ValType::V128], 8);
simd_lane_access!(I32x4ExtractLane, i32x4_extract_lane, &[ValType::V128] => &[ValType::I32], 4);
simd_lane_access!(I32x4ReplaceLane, i32x4_replace_lane, &[ValType::V128, ValType::I32] => &[ValType::V128], 4);
simd_lane_access!(I64x2ExtractLane, i64x2_extract_lane, &[ValType::V128] => &[ValType::I64], 2);
simd_lane_access!(I64x2ReplaceLane, i64x2_replace_lane, &[ValType::V128, ValType::I64] => &[ValType::V128], 2);
simd_lane_access!(F32x4ExtractLane, f32x4_extract_lane, &[ValType::V128] => &[ValType::F32], 4);
simd_lane_access!(F32x4ReplaceLane, f32x4_replace_lane, &[ValType::V128, ValType::F32] => &[ValType::V128], 4);
simd_lane_access!(F64x2ExtractLane, f64x2_extract_lane, &[ValType::V128] => &[ValType::F64], 2);
simd_lane_access!(F64x2ReplaceLane, f64x2_replace_lane, &[ValType::V128, ValType::F64] => &[ValType::V128], 2);

macro_rules! simd_binop {
    ($instruction:ident, $generator_fn_name:ident) => {
        fn $generator_fn_name(
            _: &mut Unstructured,
            module: &Module,
            builder: &mut CodeBuilder,

            instructions: &mut Vec<Instruction>,
        ) -> Result<()> {
            builder.pop_operands(module, &[ValType::V128, ValType::V128]);
            builder.push_operands(&[ValType::V128]);
            instructions.push(Instruction::$instruction);
            Ok(())
        }
    };
}

macro_rules! simd_unop {
    ($instruction:ident, $generator_fn_name:ident) => {
        simd_unop!($instruction, $generator_fn_name, V128 -> V128);
    };

    ($instruction:ident, $generator_fn_name:ident, $in_type:ident -> $out_type:ident) => {
        fn $generator_fn_name(
            _: &mut Unstructured,
            module: &Module,
            builder: &mut CodeBuilder,

       instructions: &mut Vec<Instruction>, ) -> Result<()> {
            builder.pop_operands(module, &[ValType::$in_type]);
            builder.push_operands(&[ValType::$out_type]);
            instructions.push(Instruction::$instruction);
            Ok(())
        }
    };
}

macro_rules! simd_ternop {
    ($instruction:ident, $generator_fn_name:ident) => {
        fn $generator_fn_name(
            _: &mut Unstructured,
            module: &Module,
            builder: &mut CodeBuilder,

            instructions: &mut Vec<Instruction>,
        ) -> Result<()> {
            builder.pop_operands(module, &[ValType::V128, ValType::V128, ValType::V128]);
            builder.push_operands(&[ValType::V128]);
            instructions.push(Instruction::$instruction);
            Ok(())
        }
    };
}

macro_rules! simd_shift {
    ($instruction:ident, $generator_fn_name:ident) => {
        fn $generator_fn_name(
            _: &mut Unstructured,
            module: &Module,
            builder: &mut CodeBuilder,

            instructions: &mut Vec<Instruction>,
        ) -> Result<()> {
            builder.pop_operands(module, &[ValType::V128, ValType::I32]);
            builder.push_operands(&[ValType::V128]);
            instructions.push(Instruction::$instruction);
            Ok(())
        }
    };
}

simd_unop!(I8x16Splat, i8x16_splat, I32 -> V128);
simd_unop!(I16x8Splat, i16x8_splat, I32 -> V128);
simd_unop!(I32x4Splat, i32x4_splat, I32 -> V128);
simd_unop!(I64x2Splat, i64x2_splat, I64 -> V128);
simd_unop!(F32x4Splat, f32x4_splat, F32 -> V128);
simd_unop!(F64x2Splat, f64x2_splat, F64 -> V128);
simd_binop!(I8x16Swizzle, i8x16_swizzle);
simd_binop!(I8x16Eq, i8x16_eq);
simd_binop!(I8x16Ne, i8x16_ne);
simd_binop!(I8x16LtS, i8x16_lt_s);
simd_binop!(I8x16LtU, i8x16_lt_u);
simd_binop!(I8x16GtS, i8x16_gt_s);
simd_binop!(I8x16GtU, i8x16_gt_u);
simd_binop!(I8x16LeS, i8x16_le_s);
simd_binop!(I8x16LeU, i8x16_le_u);
simd_binop!(I8x16GeS, i8x16_ge_s);
simd_binop!(I8x16GeU, i8x16_ge_u);
simd_binop!(I16x8Eq, i16x8_eq);
simd_binop!(I16x8Ne, i16x8_ne);
simd_binop!(I16x8LtS, i16x8_lt_s);
simd_binop!(I16x8LtU, i16x8_lt_u);
simd_binop!(I16x8GtS, i16x8_gt_s);
simd_binop!(I16x8GtU, i16x8_gt_u);
simd_binop!(I16x8LeS, i16x8_le_s);
simd_binop!(I16x8LeU, i16x8_le_u);
simd_binop!(I16x8GeS, i16x8_ge_s);
simd_binop!(I16x8GeU, i16x8_ge_u);
simd_binop!(I32x4Eq, i32x4_eq);
simd_binop!(I32x4Ne, i32x4_ne);
simd_binop!(I32x4LtS, i32x4_lt_s);
simd_binop!(I32x4LtU, i32x4_lt_u);
simd_binop!(I32x4GtS, i32x4_gt_s);
simd_binop!(I32x4GtU, i32x4_gt_u);
simd_binop!(I32x4LeS, i32x4_le_s);
simd_binop!(I32x4LeU, i32x4_le_u);
simd_binop!(I32x4GeS, i32x4_ge_s);
simd_binop!(I32x4GeU, i32x4_ge_u);
simd_binop!(I64x2Eq, i64x2_eq);
simd_binop!(I64x2Ne, i64x2_ne);
simd_binop!(I64x2LtS, i64x2_lt_s);
simd_binop!(I64x2GtS, i64x2_gt_s);
simd_binop!(I64x2LeS, i64x2_le_s);
simd_binop!(I64x2GeS, i64x2_ge_s);
simd_binop!(F32x4Eq, f32x4_eq);
simd_binop!(F32x4Ne, f32x4_ne);
simd_binop!(F32x4Lt, f32x4_lt);
simd_binop!(F32x4Gt, f32x4_gt);
simd_binop!(F32x4Le, f32x4_le);
simd_binop!(F32x4Ge, f32x4_ge);
simd_binop!(F64x2Eq, f64x2_eq);
simd_binop!(F64x2Ne, f64x2_ne);
simd_binop!(F64x2Lt, f64x2_lt);
simd_binop!(F64x2Gt, f64x2_gt);
simd_binop!(F64x2Le, f64x2_le);
simd_binop!(F64x2Ge, f64x2_ge);
simd_unop!(V128Not, v128_not);
simd_binop!(V128And, v128_and);
simd_binop!(V128AndNot, v128_and_not);
simd_binop!(V128Or, v128_or);
simd_binop!(V128Xor, v128_xor);
simd_unop!(V128AnyTrue, v128_any_true, V128 -> I32);
simd_unop!(I8x16Abs, i8x16_abs);
simd_unop!(I8x16Neg, i8x16_neg);
simd_unop!(I8x16Popcnt, i8x16_popcnt);
simd_unop!(I8x16AllTrue, i8x16_all_true, V128 -> I32);
simd_unop!(I8x16Bitmask, i8x16_bitmask, V128 -> I32);
simd_binop!(I8x16NarrowI16x8S, i8x16_narrow_i16x8s);
simd_binop!(I8x16NarrowI16x8U, i8x16_narrow_i16x8u);
simd_shift!(I8x16Shl, i8x16_shl);
simd_shift!(I8x16ShrS, i8x16_shr_s);
simd_shift!(I8x16ShrU, i8x16_shr_u);
simd_binop!(I8x16Add, i8x16_add);
simd_binop!(I8x16AddSatS, i8x16_add_sat_s);
simd_binop!(I8x16AddSatU, i8x16_add_sat_u);
simd_binop!(I8x16Sub, i8x16_sub);
simd_binop!(I8x16SubSatS, i8x16_sub_sat_s);
simd_binop!(I8x16SubSatU, i8x16_sub_sat_u);
simd_binop!(I8x16MinS, i8x16_min_s);
simd_binop!(I8x16MinU, i8x16_min_u);
simd_binop!(I8x16MaxS, i8x16_max_s);
simd_binop!(I8x16MaxU, i8x16_max_u);
simd_binop!(I8x16AvgrU, i8x16_avgr_u);
simd_unop!(I16x8ExtAddPairwiseI8x16S, i16x8_extadd_pairwise_i8x16s);
simd_unop!(I16x8ExtAddPairwiseI8x16U, i16x8_extadd_pairwise_i8x16u);
simd_unop!(I16x8Abs, i16x8_abs);
simd_unop!(I16x8Neg, i16x8_neg);
simd_binop!(I16x8Q15MulrSatS, i16x8q15_mulr_sat_s);
simd_unop!(I16x8AllTrue, i16x8_all_true, V128 -> I32);
simd_unop!(I16x8Bitmask, i16x8_bitmask, V128 -> I32);
simd_binop!(I16x8NarrowI32x4S, i16x8_narrow_i32x4s);
simd_binop!(I16x8NarrowI32x4U, i16x8_narrow_i32x4u);
simd_unop!(I16x8ExtendLowI8x16S, i16x8_extend_low_i8x16s);
simd_unop!(I16x8ExtendHighI8x16S, i16x8_extend_high_i8x16s);
simd_unop!(I16x8ExtendLowI8x16U, i16x8_extend_low_i8x16u);
simd_unop!(I16x8ExtendHighI8x16U, i16x8_extend_high_i8x16u);
simd_shift!(I16x8Shl, i16x8_shl);
simd_shift!(I16x8ShrS, i16x8_shr_s);
simd_shift!(I16x8ShrU, i16x8_shr_u);
simd_binop!(I16x8Add, i16x8_add);
simd_binop!(I16x8AddSatS, i16x8_add_sat_s);
simd_binop!(I16x8AddSatU, i16x8_add_sat_u);
simd_binop!(I16x8Sub, i16x8_sub);
simd_binop!(I16x8SubSatS, i16x8_sub_sat_s);
simd_binop!(I16x8SubSatU, i16x8_sub_sat_u);
simd_binop!(I16x8Mul, i16x8_mul);
simd_binop!(I16x8MinS, i16x8_min_s);
simd_binop!(I16x8MinU, i16x8_min_u);
simd_binop!(I16x8MaxS, i16x8_max_s);
simd_binop!(I16x8MaxU, i16x8_max_u);
simd_binop!(I16x8AvgrU, i16x8_avgr_u);
simd_binop!(I16x8ExtMulLowI8x16S, i16x8_extmul_low_i8x16s);
simd_binop!(I16x8ExtMulHighI8x16S, i16x8_extmul_high_i8x16s);
simd_binop!(I16x8ExtMulLowI8x16U, i16x8_extmul_low_i8x16u);
simd_binop!(I16x8ExtMulHighI8x16U, i16x8_extmul_high_i8x16u);
simd_unop!(I32x4ExtAddPairwiseI16x8S, i32x4_extadd_pairwise_i16x8s);
simd_unop!(I32x4ExtAddPairwiseI16x8U, i32x4_extadd_pairwise_i16x8u);
simd_unop!(I32x4Abs, i32x4_abs);
simd_unop!(I32x4Neg, i32x4_neg);
simd_unop!(I32x4AllTrue, i32x4_all_true, V128 -> I32);
simd_unop!(I32x4Bitmask, i32x4_bitmask, V128 -> I32);
simd_unop!(I32x4ExtendLowI16x8S, i32x4_extend_low_i16x8s);
simd_unop!(I32x4ExtendHighI16x8S, i32x4_extend_high_i16x8s);
simd_unop!(I32x4ExtendLowI16x8U, i32x4_extend_low_i16x8u);
simd_unop!(I32x4ExtendHighI16x8U, i32x4_extend_high_i16x8u);
simd_shift!(I32x4Shl, i32x4_shl);
simd_shift!(I32x4ShrS, i32x4_shr_s);
simd_shift!(I32x4ShrU, i32x4_shr_u);
simd_binop!(I32x4Add, i32x4_add);
simd_binop!(I32x4Sub, i32x4_sub);
simd_binop!(I32x4Mul, i32x4_mul);
simd_binop!(I32x4MinS, i32x4_min_s);
simd_binop!(I32x4MinU, i32x4_min_u);
simd_binop!(I32x4MaxS, i32x4_max_s);
simd_binop!(I32x4MaxU, i32x4_max_u);
simd_binop!(I32x4DotI16x8S, i32x4_dot_i16x8s);
simd_binop!(I32x4ExtMulLowI16x8S, i32x4_extmul_low_i16x8s);
simd_binop!(I32x4ExtMulHighI16x8S, i32x4_extmul_high_i16x8s);
simd_binop!(I32x4ExtMulLowI16x8U, i32x4_extmul_low_i16x8u);
simd_binop!(I32x4ExtMulHighI16x8U, i32x4_extmul_high_i16x8u);
simd_unop!(I64x2Abs, i64x2_abs);
simd_unop!(I64x2Neg, i64x2_neg);
simd_unop!(I64x2AllTrue, i64x2_all_true, V128 -> I32);
simd_unop!(I64x2Bitmask, i64x2_bitmask, V128 -> I32);
simd_unop!(I64x2ExtendLowI32x4S, i64x2_extend_low_i32x4s);
simd_unop!(I64x2ExtendHighI32x4S, i64x2_extend_high_i32x4s);
simd_unop!(I64x2ExtendLowI32x4U, i64x2_extend_low_i32x4u);
simd_unop!(I64x2ExtendHighI32x4U, i64x2_extend_high_i32x4u);
simd_shift!(I64x2Shl, i64x2_shl);
simd_shift!(I64x2ShrS, i64x2_shr_s);
simd_shift!(I64x2ShrU, i64x2_shr_u);
simd_binop!(I64x2Add, i64x2_add);
simd_binop!(I64x2Sub, i64x2_sub);
simd_binop!(I64x2Mul, i64x2_mul);
simd_binop!(I64x2ExtMulLowI32x4S, i64x2_extmul_low_i32x4s);
simd_binop!(I64x2ExtMulHighI32x4S, i64x2_extmul_high_i32x4s);
simd_binop!(I64x2ExtMulLowI32x4U, i64x2_extmul_low_i32x4u);
simd_binop!(I64x2ExtMulHighI32x4U, i64x2_extmul_high_i32x4u);
simd_unop!(F32x4Ceil, f32x4_ceil);
simd_unop!(F32x4Floor, f32x4_floor);
simd_unop!(F32x4Trunc, f32x4_trunc);
simd_unop!(F32x4Nearest, f32x4_nearest);
simd_unop!(F32x4Abs, f32x4_abs);
simd_unop!(F32x4Neg, f32x4_neg);
simd_unop!(F32x4Sqrt, f32x4_sqrt);
simd_binop!(F32x4Add, f32x4_add);
simd_binop!(F32x4Sub, f32x4_sub);
simd_binop!(F32x4Mul, f32x4_mul);
simd_binop!(F32x4Div, f32x4_div);
simd_binop!(F32x4Min, f32x4_min);
simd_binop!(F32x4Max, f32x4_max);
simd_binop!(F32x4PMin, f32x4p_min);
simd_binop!(F32x4PMax, f32x4p_max);
simd_unop!(F64x2Ceil, f64x2_ceil);
simd_unop!(F64x2Floor, f64x2_floor);
simd_unop!(F64x2Trunc, f64x2_trunc);
simd_unop!(F64x2Nearest, f64x2_nearest);
simd_unop!(F64x2Abs, f64x2_abs);
simd_unop!(F64x2Neg, f64x2_neg);
simd_unop!(F64x2Sqrt, f64x2_sqrt);
simd_binop!(F64x2Add, f64x2_add);
simd_binop!(F64x2Sub, f64x2_sub);
simd_binop!(F64x2Mul, f64x2_mul);
simd_binop!(F64x2Div, f64x2_div);
simd_binop!(F64x2Min, f64x2_min);
simd_binop!(F64x2Max, f64x2_max);
simd_binop!(F64x2PMin, f64x2p_min);
simd_binop!(F64x2PMax, f64x2p_max);
simd_unop!(I32x4TruncSatF32x4S, i32x4_trunc_sat_f32x4s);
simd_unop!(I32x4TruncSatF32x4U, i32x4_trunc_sat_f32x4u);
simd_unop!(F32x4ConvertI32x4S, f32x4_convert_i32x4s);
simd_unop!(F32x4ConvertI32x4U, f32x4_convert_i32x4u);
simd_unop!(I32x4TruncSatF64x2SZero, i32x4_trunc_sat_f64x2s_zero);
simd_unop!(I32x4TruncSatF64x2UZero, i32x4_trunc_sat_f64x2u_zero);
simd_unop!(F64x2ConvertLowI32x4S, f64x2_convert_low_i32x4s);
simd_unop!(F64x2ConvertLowI32x4U, f64x2_convert_low_i32x4u);
simd_unop!(F32x4DemoteF64x2Zero, f32x4_demote_f64x2_zero);
simd_unop!(F64x2PromoteLowF32x4, f64x2_promote_low_f32x4);
simd_ternop!(V128Bitselect, v128_bitselect);
simd_binop!(I8x16RelaxedSwizzle, i8x16_relaxed_swizzle);
simd_unop!(I32x4RelaxedTruncF32x4S, i32x4_relaxed_trunc_f32x4s);
simd_unop!(I32x4RelaxedTruncF32x4U, i32x4_relaxed_trunc_f32x4u);
simd_unop!(I32x4RelaxedTruncF64x2SZero, i32x4_relaxed_trunc_f64x2s_zero);
simd_unop!(I32x4RelaxedTruncF64x2UZero, i32x4_relaxed_trunc_f64x2u_zero);
simd_ternop!(F32x4RelaxedMadd, f32x4_relaxed_madd);
simd_ternop!(F32x4RelaxedNmadd, f32x4_relaxed_nmadd);
simd_ternop!(F64x2RelaxedMadd, f64x2_relaxed_madd);
simd_ternop!(F64x2RelaxedNmadd, f64x2_relaxed_nmadd);
simd_ternop!(I8x16RelaxedLaneselect, i8x16_relaxed_laneselect);
simd_ternop!(I16x8RelaxedLaneselect, i16x8_relaxed_laneselect);
simd_ternop!(I32x4RelaxedLaneselect, i32x4_relaxed_laneselect);
simd_ternop!(I64x2RelaxedLaneselect, i64x2_relaxed_laneselect);
simd_binop!(F32x4RelaxedMin, f32x4_relaxed_min);
simd_binop!(F32x4RelaxedMax, f32x4_relaxed_max);
simd_binop!(F64x2RelaxedMin, f64x2_relaxed_min);
simd_binop!(F64x2RelaxedMax, f64x2_relaxed_max);
simd_binop!(I16x8RelaxedQ15mulrS, i16x8_relaxed_q15mulr_s);
simd_binop!(I16x8RelaxedDotI8x16I7x16S, i16x8_relaxed_dot_i8x16_i7x16_s);
simd_ternop!(
    I32x4RelaxedDotI8x16I7x16AddS,
    i32x4_relaxed_dot_i8x16_i7x16_add_s
);

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-smith-0.210.0/src/core/code_builder/no_traps.rs

Source (jump to first uncovered line)
use crate::core::*;
use wasm_encoder::Instruction;

use super::CodeBuilder;

// For loads, we dynamically check whether the load will
// trap, and if it will then we generate a dummy value to
// use instead.
pub(crate) fn load<'a>(
    inst: Instruction<'a>,
    module: &Module,
    builder: &mut CodeBuilder,
    insts: &mut Vec<Instruction<'a>>,
) {
    let memarg = get_memarg(&inst);
    let memory = &module.memories[memarg.memory_index as usize];
    let address_type = if memory.memory64 {
        ValType::I64
    } else {
        ValType::I32
    };
    // Add a temporary local to hold this load's address.
    let address_local = builder.alloc_local(address_type);

    // Add a temporary local to hold the result of this load.
    let load_type = type_of_memory_access(&inst);
    let result_local = builder.alloc_local(load_type);

    // [address:address_type]
    insts.push(Instruction::LocalSet(address_local));
    // []
    insts.push(Instruction::Block(wasm_encoder::BlockType::Empty));
    {
        // []
        insts.push(Instruction::Block(wasm_encoder::BlockType::Empty));
        {
            // []
            insts.push(Instruction::MemorySize(memarg.memory_index));
            // [mem_size_in_pages:address_type]
            insts.push(int_const_inst(
                address_type,
                crate::page_size(memory).into(),
            ));
            // [mem_size_in_pages:address_type wasm_page_size:address_type]
            insts.push(int_mul_inst(address_type));
            // [mem_size_in_bytes:address_type]
            insts.push(int_const_inst(
                address_type,
                (memarg.offset + size_of_type_in_memory(load_type)) as i64,
            ));
            // [mem_size_in_bytes:address_type offset_and_size:address_type]
            insts.push(Instruction::LocalGet(address_local));
            // [mem_size_in_bytes:address_type offset_and_size:address_type address:address_type]
            insts.push(int_add_inst(address_type));
            // [mem_size_in_bytes:address_type highest_byte_accessed:address_type]
            insts.push(int_le_u_inst(address_type));
            // [load_will_trap:i32]
            insts.push(Instruction::BrIf(0));
            // []
            insts.push(Instruction::LocalGet(address_local));
            // [address:address_type]
            insts.push(int_const_inst(address_type, 0));
            // [address:address_type 0:address_type]
            insts.push(int_le_s_inst(address_type));
            // [load_will_trap:i32]
            insts.push(Instruction::BrIf(0));
            // []
            insts.push(Instruction::LocalGet(address_local));
            // [address:address_type]
            insts.push(inst);
            // [result:load_type]
            insts.push(Instruction::LocalSet(result_local));
            // []
            insts.push(Instruction::Br(1));
            // <unreachable>
        }
        // []
        insts.push(Instruction::End);
        // []
        insts.push(dummy_value_inst(load_type));
        // [dummy_value:load_type]
        insts.push(Instruction::LocalSet(result_local));
        // []
    }
    // []
    insts.push(Instruction::End);
    // []
    insts.push(Instruction::LocalGet(result_local));
    // [result:load_type]
}

// Stores are similar to loads: we check whether the store
// will trap, and if it will then we just drop the value.
pub(crate) fn store<'a>(
    inst: Instruction<'a>,
    module: &Module,
    builder: &mut CodeBuilder,
    insts: &mut Vec<Instruction<'a>>,
) {
    let memarg = get_memarg(&inst);
    let memory = &module.memories[memarg.memory_index as usize];
    let address_type = if memory.memory64 {
        ValType::I64
    } else {
        ValType::I32
    };

    // Add a temporary local to hold this store's address.
    let address_local = builder.alloc_local(address_type);

    // Add a temporary local to hold the value to store.
    let store_type = type_of_memory_access(&inst);
    let value_local = builder.alloc_local(store_type);

    // [address:address_type value:store_type]
    insts.push(Instruction::LocalSet(value_local));
    // [address:address_type]
    insts.push(Instruction::LocalSet(address_local));
    // []
    insts.push(Instruction::MemorySize(memarg.memory_index));
    // [mem_size_in_pages:address_type]
    insts.push(int_const_inst(
        address_type,
        crate::page_size(memory).into(),
    ));
    // [mem_size_in_pages:address_type wasm_page_size:address_type]
    insts.push(int_mul_inst(address_type));
    // [mem_size_in_bytes:address_type]
    insts.push(int_const_inst(
        address_type,
        (memarg.offset + size_of_type_in_memory(store_type)) as i64,
    ));
    // [mem_size_in_bytes:address_type offset_and_size:address_type]
    insts.push(Instruction::LocalGet(address_local));
    // [mem_size_in_bytes:address_type offset_and_size:address_type address:address_type]
    insts.push(int_add_inst(address_type));
    // [mem_size_in_bytes:address_type highest_byte_accessed:address_type]
    insts.push(int_le_u_inst(address_type));
    // [store_will_trap:i32]
    insts.push(Instruction::If(BlockType::Empty));
    insts.push(Instruction::Else);
    {
        // []
        insts.push(Instruction::LocalGet(address_local));
        // [address:address_type]
        insts.push(int_const_inst(address_type, 0));
        // [address:address_type 0:address_type]
        insts.push(int_le_s_inst(address_type));
        // [load_will_trap:i32]
        insts.push(Instruction::If(BlockType::Empty));
        insts.push(Instruction::Else);
        {
            // []
            insts.push(Instruction::LocalGet(address_local));
            // [address:address_type]
            insts.push(Instruction::LocalGet(value_local));
            // [address:address_type value:store_type]
            insts.push(inst);
            // []
        }
        insts.push(Instruction::End);
    }
    // []
    insts.push(Instruction::End);
}

// Unsigned integer division and remainder will trap when
// the divisor is 0. To avoid the trap, we will set any 0
// divisors to 1 prior to the operation.
//
// The code below is equivalent to this expression:
//
//     local.set $temp_divisor
//     (select (i32.eqz (local.get $temp_divisor) (i32.const 1) (local.get $temp_divisor))
pub(crate) fn unsigned_div_rem<'a>(
    inst: Instruction<'a>,
    builder: &mut CodeBuilder,
    insts: &mut Vec<Instruction<'a>>,
) {
    let op_type = type_of_integer_operation(&inst);
    let temp_divisor = builder.alloc_local(op_type);

    // [dividend:op_type divisor:op_type]
    insts.push(Instruction::LocalSet(temp_divisor));
    // [dividend:op_type]
    insts.push(int_const_inst(op_type, 1));
    // [dividend:op_type 1:op_type]
    insts.push(Instruction::LocalGet(temp_divisor));
    // [dividend:op_type 1:op_type divisor:op_type]
    insts.push(Instruction::LocalGet(temp_divisor));
    // [dividend:op_type 1:op_type divisor:op_type divisor:op_type]
    insts.push(eqz_inst(op_type));
    // [dividend:op_type 1:op_type divisor:op_type is_zero:i32]
    insts.push(Instruction::Select);
    // [dividend:op_type divisor:op_type]
    insts.push(inst);
    // [result:op_type]
}

pub(crate) fn trunc<'a>(
    inst: Instruction<'a>,
    builder: &mut CodeBuilder,
    insts: &mut Vec<Instruction<'a>>,
) {
    // If NaN or ±inf, replace with dummy value. Our method of checking for NaN
    // is to use `ne` because NaN is the only value that is not equal to itself
    let conv_type = type_of_float_conversion(&inst);
    let temp_float = builder.alloc_local(conv_type);
    // [input:conv_type]
    insts.push(Instruction::LocalTee(temp_float));
    // [input:conv_type]
    insts.push(Instruction::LocalGet(temp_float));
    // [input:conv_type input:conv_type]
    insts.push(ne_inst(conv_type));
    // [is_nan:i32]
    insts.push(Instruction::LocalGet(temp_float));
    // [is_nan:i32 input:conv_type]
    insts.push(flt_inf_const_inst(conv_type));
    // [is_nan:i32 input:conv_type inf:conv_type]
    insts.push(eq_inst(conv_type));
    // [is_nan:i32 is_inf:i32]
    insts.push(Instruction::LocalGet(temp_float));
    // [is_nan:i32 is_inf:i32 input:conv_type]
    insts.push(flt_neg_inf_const_inst(conv_type));
    // [is_nan:i32 is_inf:i32 input:conv_type neg_inf:conv_type]
    insts.push(eq_inst(conv_type));
    // [is_nan:i32 is_inf:i32 is_neg_inf:i32]
    insts.push(Instruction::I32Or);
    // [is_nan:i32 is_±inf:i32]
    insts.push(Instruction::I32Or);
    // [is_nan_or_inf:i32]
    insts.push(Instruction::If(BlockType::Empty));
    {
        // []
        insts.push(dummy_value_inst(conv_type));
        // [0:conv_type]
        insts.push(Instruction::LocalSet(temp_float));
        // []
    }
    insts.push(Instruction::End);
    // []
    insts.push(Instruction::LocalGet(temp_float));
    // [input_or_0:conv_type]

    // first ensure that it is >= the min value of our target type
    insts.push(min_input_const_for_trunc(&inst));
    // [input_or_0:conv_type min_value_of_target_type:conv_type]
    insts.push(flt_lt_inst(conv_type));
    // [input_lt_min:i32]
    insts.push(Instruction::If(BlockType::Empty));
    {
        // []
        insts.push(min_input_const_for_trunc(&inst));
        // [min_value_of_target_type:conv_type]
        insts.push(Instruction::LocalSet(temp_float));
    }
    insts.push(Instruction::End);
    // []
    insts.push(Instruction::LocalGet(temp_float));
    // [coerced_input:conv_type]

    // next ensure that it is  <= the max value of our target type
    insts.push(max_input_const_for_trunc(&inst));
    // [input_or_0:conv_type max_value_of_target_type:conv_type]
    insts.push(flt_gt_inst(conv_type));
    // [input_gt_min:i32]
    insts.push(Instruction::If(BlockType::Empty));
    {
        // []
        insts.push(max_input_const_for_trunc(&inst));
        // [max_value_of_target_type:conv_type]
        insts.push(Instruction::LocalSet(temp_float));
    }
    insts.push(Instruction::End);
    // []
    insts.push(Instruction::LocalGet(temp_float));
    // [coerced_input:conv_type]
    insts.push(inst);
}

// Signed division and remainder will trap in the following instances:
//     - The divisor is 0
//     - The result of the division is 2^(n-1)
pub(crate) fn signed_div_rem<'a>(
    inst: Instruction<'a>,
    builder: &mut CodeBuilder,
    insts: &mut Vec<Instruction<'a>>,
) {
    // If divisor is 0, replace with 1
    let op_type = type_of_integer_operation(&inst);
    let temp_divisor = builder.alloc_local(op_type);
    // [dividend:op_type divisor:op_type]
    insts.push(Instruction::LocalSet(temp_divisor));
    // [dividend:op_type]
    insts.push(int_const_inst(op_type, 1));
    // [dividend:op_type 1:op_type]
    insts.push(Instruction::LocalGet(temp_divisor));
    // [dividend:op_type 1:op_type divisor:op_type]
    insts.push(Instruction::LocalGet(temp_divisor));
    // [dividend:op_type 1:op_type divisor:op_type divisor:op_type]
    insts.push(eqz_inst(op_type));
    // [dividend:op_type 1:op_type divisor:op_type is_zero:i32]
    insts.push(Instruction::Select);
    // [dividend:op_type divisor:op_type]
    // If dividend and divisor are -int.max and -1, replace
    // divisor with 1.
    let temp_dividend = builder.alloc_local(op_type);
    insts.push(Instruction::LocalSet(temp_divisor));
    // [dividend:op_type]
    insts.push(Instruction::LocalSet(temp_dividend));
    // []
    insts.push(Instruction::Block(wasm_encoder::BlockType::Empty));
    {
        insts.push(Instruction::Block(wasm_encoder::BlockType::Empty));
        {
            // []
            insts.push(Instruction::LocalGet(temp_dividend));
            // [dividend:op_type]
            insts.push(Instruction::LocalGet(temp_divisor));
            // [dividend:op_type divisor:op_type]
            insts.push(Instruction::LocalSet(temp_divisor));
            // [dividend:op_type]
            insts.push(Instruction::LocalTee(temp_dividend));
            // [dividend:op_type]
            insts.push(int_min_const_inst(op_type));
            // [dividend:op_type int_min:op_type]
            insts.push(ne_inst(op_type));
            // [not_int_min:i32]
            insts.push(Instruction::BrIf(0));
            // []
            insts.push(Instruction::LocalGet(temp_divisor));
            // [divisor:op_type]
            insts.push(int_const_inst(op_type, -1));
            // [divisor:op_type -1:op_type]
            insts.push(ne_inst(op_type));
            // [not_neg_one:i32]
            insts.push(Instruction::BrIf(0));
            // []
            insts.push(int_const_inst(op_type, 1));
            // [divisor:op_type]
            insts.push(Instruction::LocalSet(temp_divisor));
            // []
            insts.push(Instruction::Br(1));
        }
        // []
        insts.push(Instruction::End);
    }
    // []
    insts.push(Instruction::End);
    // []
    insts.push(Instruction::LocalGet(temp_dividend));
    // [dividend:op_type]
    insts.push(Instruction::LocalGet(temp_divisor));
    // [dividend:op_type divisor:op_type]
    insts.push(inst);
}

fn get_memarg(inst: &Instruction) -> wasm_encoder::MemArg {
    match *inst {
        Instruction::I32Load(memarg)
        | Instruction::I64Load(memarg)
        | Instruction::F32Load(memarg)
        | Instruction::F64Load(memarg)
        | Instruction::I32Load8S(memarg)
        | Instruction::I32Load8U(memarg)
        | Instruction::I32Load16S(memarg)
        | Instruction::I32Load16U(memarg)
        | Instruction::I64Load8S(memarg)
        | Instruction::I64Load8U(memarg)
        | Instruction::I64Load16S(memarg)
        | Instruction::I64Load16U(memarg)
        | Instruction::I64Load32S(memarg)
        | Instruction::I64Load32U(memarg)
        | Instruction::V128Load(memarg)
        | Instruction::V128Load8x8S(memarg)
        | Instruction::V128Load8x8U(memarg)
        | Instruction::V128Load16x4S(memarg)
        | Instruction::V128Load16x4U(memarg)
        | Instruction::V128Load32x2S(memarg)
        | Instruction::V128Load32x2U(memarg)
        | Instruction::V128Load8Splat(memarg)
        | Instruction::V128Load16Splat(memarg)
        | Instruction::V128Load32Splat(memarg)
        | Instruction::V128Load64Splat(memarg)
        | Instruction::V128Load32Zero(memarg)
        | Instruction::V128Load64Zero(memarg)
        | Instruction::I32Store(memarg)
        | Instruction::I64Store(memarg)
        | Instruction::F32Store(memarg)
        | Instruction::F64Store(memarg)
        | Instruction::I32Store8(memarg)
        | Instruction::I32Store16(memarg)
        | Instruction::I64Store8(memarg)
        | Instruction::I64Store16(memarg)
        | Instruction::I64Store32(memarg)
        | Instruction::V128Store(memarg) => memarg,
        _ => unreachable!(),
    }
}

fn dummy_value_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::I32 => Instruction::I32Const(0),
        ValType::I64 => Instruction::I64Const(0),
        ValType::F32 => Instruction::F32Const(0.0),
        ValType::F64 => Instruction::F64Const(0.0),
        ValType::V128 => Instruction::V128Const(0),
        ValType::Ref(ty) => {
            assert!(ty.nullable);
            Instruction::RefNull(ty.heap_type)
        }
    }
}

fn eq_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::F32 => Instruction::F32Eq,
        ValType::F64 => Instruction::F64Eq,
        ValType::I32 => Instruction::I32Eq,
        ValType::I64 => Instruction::I64Eq,
        _ => panic!("not a numeric type"),
    }
}

fn eqz_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::I32 => Instruction::I32Eqz,
        ValType::I64 => Instruction::I64Eqz,
        _ => panic!("not an integer type"),
    }
}

fn type_of_integer_operation(inst: &Instruction) -> ValType {
    match inst {
        Instruction::I32DivU
        | Instruction::I32DivS
        | Instruction::I32RemU
        | Instruction::I32RemS => ValType::I32,
        Instruction::I64RemU
        | Instruction::I64DivU
        | Instruction::I64DivS
        | Instruction::I64RemS => ValType::I64,
        _ => panic!("not integer division or remainder"),
    }
}

fn type_of_float_conversion(inst: &Instruction) -> ValType {
    match inst {
        Instruction::I32TruncF32S
        | Instruction::I32TruncF32U
        | Instruction::I64TruncF32S
        | Instruction::I64TruncF32U => ValType::F32,
        Instruction::I32TruncF64S
        | Instruction::I32TruncF64U
        | Instruction::I64TruncF64S
        | Instruction::I64TruncF64U => ValType::F64,
        _ => panic!("not a float -> integer conversion"),
    }
}

fn min_input_const_for_trunc<'a>(inst: &Instruction) -> Instruction<'a> {
    // This is the minimum float value that is representable as an i64
    let min_f64 = -9_223_372_036_854_775_000f64;
    let min_f32 = -9_223_372_000_000_000_000f32;

    // This is the minimum float value that is representable as as i32
    let min_f32_as_i32 = -2_147_483_500f32;
    match inst {
        Instruction::I32TruncF32S => Instruction::F32Const(min_f32_as_i32),
        Instruction::I32TruncF32U => Instruction::F32Const(0.0),
        Instruction::I64TruncF32S => Instruction::F32Const(min_f32),
        Instruction::I64TruncF32U => Instruction::F32Const(0.0),
        Instruction::I32TruncF64S => Instruction::F64Const(i32::MIN as f64),
        Instruction::I32TruncF64U => Instruction::F64Const(0.0),
        Instruction::I64TruncF64S => Instruction::F64Const(min_f64),
        Instruction::I64TruncF64U => Instruction::F64Const(0.0),
        _ => panic!("not a trunc instruction"),
    }
}

fn max_input_const_for_trunc<'a>(inst: &Instruction) -> Instruction<'a> {
    // This is the maximum float value that is representable as as i64
    let max_f64_as_i64 = 9_223_372_036_854_775_000f64;
    let max_f32_as_i64 = 9_223_371_500_000_000_000f32;

    // This is the maximum float value that is representable as as i32
    let max_f32_as_i32 = 2_147_483_500f32;
    match inst {
        Instruction::I32TruncF32S | Instruction::I32TruncF32U => {
            Instruction::F32Const(max_f32_as_i32)
        }
        Instruction::I64TruncF32S | Instruction::I64TruncF32U => {
            Instruction::F32Const(max_f32_as_i64)
        }
        Instruction::I32TruncF64S | Instruction::I32TruncF64U => {
            Instruction::F64Const(i32::MAX as f64)
        }
        Instruction::I64TruncF64S | Instruction::I64TruncF64U => {
            Instruction::F64Const(max_f64_as_i64)
        }
        _ => panic!("not a trunc instruction"),
    }
}

fn type_of_memory_access(inst: &Instruction) -> ValType {
    match inst {
        Instruction::I32Load(_)
        | Instruction::I32Load8S(_)
        | Instruction::I32Load8U(_)
        | Instruction::I32Load16S(_)
        | Instruction::I32Load16U(_)
        | Instruction::I32Store(_)
        | Instruction::I32Store8(_)
        | Instruction::I32Store16(_) => ValType::I32,

        Instruction::I64Load(_)
        | Instruction::I64Load8S(_)
        | Instruction::I64Load8U(_)
        | Instruction::I64Load16S(_)
        | Instruction::I64Load16U(_)
        | Instruction::I64Load32S(_)
        | Instruction::I64Load32U(_)
        | Instruction::I64Store(_)
        | Instruction::I64Store8(_)
        | Instruction::I64Store16(_)
        | Instruction::I64Store32(_) => ValType::I64,

        Instruction::F32Load(_) | Instruction::F32Store(_) => ValType::F32,

        Instruction::F64Load(_) | Instruction::F64Store(_) => ValType::F64,

        Instruction::V128Load { .. }
        | Instruction::V128Load8x8S { .. }
        | Instruction::V128Load8x8U { .. }
        | Instruction::V128Load16x4S { .. }
        | Instruction::V128Load16x4U { .. }
        | Instruction::V128Load32x2S { .. }
        | Instruction::V128Load32x2U { .. }
        | Instruction::V128Load8Splat { .. }
        | Instruction::V128Load16Splat { .. }
        | Instruction::V128Load32Splat { .. }
        | Instruction::V128Load64Splat { .. }
        | Instruction::V128Load32Zero { .. }
        | Instruction::V128Load64Zero { .. }
        | Instruction::V128Store { .. } => ValType::V128,

        _ => panic!("not a memory access instruction"),
    }
}

fn int_min_const_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::I32 => Instruction::I32Const(i32::MIN),
        ValType::I64 => Instruction::I64Const(i64::MIN),
        _ => panic!("not an int type"),
    }
}

fn int_const_inst<'a>(ty: ValType, x: i64) -> Instruction<'a> {
    match ty {
        ValType::I32 => Instruction::I32Const(x as i32),
        ValType::I64 => Instruction::I64Const(x),
        _ => panic!("not an int type"),
    }
}

fn int_mul_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::I32 => Instruction::I32Mul,
        ValType::I64 => Instruction::I64Mul,
        _ => panic!("not an int type"),
    }
}

fn int_add_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::I32 => Instruction::I32Add,
        ValType::I64 => Instruction::I64Add,
        _ => panic!("not an int type"),
    }
}

fn int_le_u_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::I32 => Instruction::I32LeU,
        ValType::I64 => Instruction::I64LeU,
        _ => panic!("not an int type"),
    }
}

fn int_le_s_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::I32 => Instruction::I32LeS,
        ValType::I64 => Instruction::I64LeS,
        _ => panic!("not an int type"),
    }
}

fn ne_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::I32 => Instruction::I32Ne,
        ValType::I64 => Instruction::I64Ne,
        ValType::F32 => Instruction::F32Ne,
        ValType::F64 => Instruction::F64Ne,
        _ => panic!("not a numeric type"),
    }
}

fn flt_lt_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::F32 => Instruction::F32Lt,
        ValType::F64 => Instruction::F64Lt,
        _ => panic!("not a float type"),
    }
}

fn flt_gt_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::F32 => Instruction::F32Gt,
        ValType::F64 => Instruction::F64Gt,
        _ => panic!("not a float type"),
    }
}

fn flt_inf_const_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::F32 => Instruction::F32Const(f32::INFINITY),
        ValType::F64 => Instruction::F64Const(f64::INFINITY),
        _ => panic!("not a float type"),
    }
}

fn flt_neg_inf_const_inst<'a>(ty: ValType) -> Instruction<'a> {
    match ty {
        ValType::F32 => Instruction::F32Const(f32::NEG_INFINITY),
        ValType::F64 => Instruction::F64Const(f64::NEG_INFINITY),
        _ => panic!("not a float type"),
    }
}

fn size_of_type_in_memory(ty: ValType) -> u64 {
    match ty {
        ValType::I32 => 4,
        ValType::I64 => 8,
        ValType::F32 => 4,
        ValType::F64 => 8,
        ValType::V128 => 16,
        ValType::Ref(_) => panic!("not a memory type"),
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-smith-0.210.0/src/core/encode.rs

Source (jump to first uncovered line)
use super::*;

impl Module {
    /// Encode this Wasm module into bytes.
    pub fn to_bytes(&self) -> Vec<u8> {
        self.encoded().finish()
    }

    fn encoded(&self) -> wasm_encoder::Module {
        let mut module = wasm_encoder::Module::new();

        self.encode_types(&mut module);
        self.encode_imports(&mut module);
        self.encode_funcs(&mut module);
        self.encode_tables(&mut module);
        self.encode_memories(&mut module);
        self.encode_tags(&mut module);
        self.encode_globals(&mut module);
        self.encode_exports(&mut module);
        self.encode_start(&mut module);
        self.encode_elems(&mut module);
        self.encode_data_count(&mut module);
        self.encode_code(&mut module);
        self.encode_data(&mut module);

        module
    }

    fn encode_types(&self, module: &mut wasm_encoder::Module) {
        if !self.should_encode_types {
            return;
        }

        let mut section = wasm_encoder::TypeSection::new();

        for group in &self.rec_groups {
            if group.end - group.start == 1 {
                let ty = &self.types[group.start];
                section.subtype(&wasm_encoder::SubType {
                    is_final: ty.is_final,
                    supertype_idx: ty.supertype,
                    composite_type: match &ty.composite_type {
                        CompositeType::Array(a) => wasm_encoder::CompositeType::Array(a.clone()),
                        CompositeType::Func(f) => {
                            wasm_encoder::CompositeType::Func(wasm_encoder::FuncType::new(
                                f.params.iter().cloned(),
                                f.results.iter().cloned(),
                            ))
                        }
                        CompositeType::Struct(s) => wasm_encoder::CompositeType::Struct(s.clone()),
                    },
                });
            } else {
                section.rec(
                    self.types[group.clone()]
                        .iter()
                        .map(|ty| wasm_encoder::SubType {
                            is_final: ty.is_final,
                            supertype_idx: ty.supertype,
                            composite_type: match &ty.composite_type {
                                CompositeType::Array(a) => {
                                    wasm_encoder::CompositeType::Array(a.clone())
                                }
                                CompositeType::Func(f) => {
                                    wasm_encoder::CompositeType::Func(wasm_encoder::FuncType::new(
                                        f.params.iter().cloned(),
                                        f.results.iter().cloned(),
                                    ))
                                }
                                CompositeType::Struct(s) => {
                                    wasm_encoder::CompositeType::Struct(s.clone())
                                }
                            },
                        }),
                );
            }
        }

        module.section(&section);
    }

    fn encode_imports(&self, module: &mut wasm_encoder::Module) {
        if !self.should_encode_imports {
            return;
        }

        let mut section = wasm_encoder::ImportSection::new();
        for im in &self.imports {
            section.import(
                &im.module,
                &im.field,
                translate_entity_type(&im.entity_type),
            );
        }
        module.section(&section);
    }

    fn encode_tags(&self, module: &mut wasm_encoder::Module) {
        if self.num_defined_tags == 0 {
            return;
        }
        let mut tags = wasm_encoder::TagSection::new();
        for tag in self.tags[self.tags.len() - self.num_defined_tags..].iter() {
            tags.tag(wasm_encoder::TagType {
                kind: wasm_encoder::TagKind::Exception,
                func_type_idx: tag.func_type_idx,
            });
        }
        module.section(&tags);
    }

    fn encode_funcs(&self, module: &mut wasm_encoder::Module) {
        if self.num_defined_funcs == 0 {
            return;
        }
        let mut funcs = wasm_encoder::FunctionSection::new();
        for (ty, _) in self.funcs[self.funcs.len() - self.num_defined_funcs..].iter() {
            funcs.function(*ty);
        }
        module.section(&funcs);
    }

    fn encode_tables(&self, module: &mut wasm_encoder::Module) {
        if self.defined_tables.is_empty() {
            return;
        }
        let mut tables = wasm_encoder::TableSection::new();
        for (t, init) in self.tables[self.tables.len() - self.defined_tables.len()..]
            .iter()
            .zip(&self.defined_tables)
        {
            match init {
                Some(init) => {
                    tables.table_with_init(*t, init);
                }
                None => {
                    tables.table(*t);
                }
            }
        }
        module.section(&tables);
    }

    fn encode_memories(&self, module: &mut wasm_encoder::Module) {
        if self.num_defined_memories == 0 {
            return;
        }
        let mut mems = wasm_encoder::MemorySection::new();
        for m in self.memories[self.memories.len() - self.num_defined_memories..].iter() {
            mems.memory(*m);
        }
        module.section(&mems);
    }

    fn encode_globals(&self, module: &mut wasm_encoder::Module) {
        if self.globals.is_empty() {
            return;
        }
        let mut globals = wasm_encoder::GlobalSection::new();
        for (idx, expr) in &self.defined_globals {
            let ty = &self.globals[*idx as usize];
            globals.global(*ty, expr);
        }
        module.section(&globals);
    }

    fn encode_exports(&self, module: &mut wasm_encoder::Module) {
        if self.exports.is_empty() {
            return;
        }
        let mut exports = wasm_encoder::ExportSection::new();
        for (name, kind, idx) in &self.exports {
            exports.export(name, *kind, *idx);
        }
        module.section(&exports);
    }

    fn encode_start(&self, module: &mut wasm_encoder::Module) {
        if let Some(f) = self.start {
            module.section(&wasm_encoder::StartSection { function_index: f });
        }
    }

    fn encode_elems(&self, module: &mut wasm_encoder::Module) {
        if self.elems.is_empty() {
            return;
        }
        let mut elems = wasm_encoder::ElementSection::new();
        for el in &self.elems {
            let elements = match &el.items {
                Elements::Expressions(es) => wasm_encoder::Elements::Expressions(el.ty, es),
                Elements::Functions(fs) => {
                    assert_eq!(el.ty, RefType::FUNCREF);
                    wasm_encoder::Elements::Functions(fs)
                }
            };
            match &el.kind {
                ElementKind::Active { table, offset } => {
                    let offset = match *offset {
                        Offset::Const32(n) => ConstExpr::i32_const(n),
                        Offset::Const64(n) => ConstExpr::i64_const(n),
                        Offset::Global(g) => ConstExpr::global_get(g),
                    };
                    elems.active(*table, &offset, elements);
                }
                ElementKind::Passive => {
                    elems.passive(elements);
                }
                ElementKind::Declared => {
                    elems.declared(elements);
                }
            }
        }
        module.section(&elems);
    }

    fn encode_data_count(&self, module: &mut wasm_encoder::Module) {
        // Without bulk memory there's no need for a data count section,
        if !self.config.bulk_memory_enabled {
            return;
        }
        // ... and also if there's no data no need for a data count section.
        if self.data.is_empty() {
            return;
        }
        module.section(&wasm_encoder::DataCountSection {
            count: u32::try_from(self.data.len()).unwrap(),
        });
    }

    fn encode_code(&self, module: &mut wasm_encoder::Module) {
        if self.code.is_empty() {
            return;
        }
        let mut code = wasm_encoder::CodeSection::new();
        for c in &self.code {
            // Skip the run-length encoding because it is a little
            // annoying to compute; use a length of one for every local.
            let mut func = wasm_encoder::Function::new(c.locals.iter().map(|l| (1, *l)));
            match &c.instructions {
                Instructions::Generated(instrs) => {
                    for instr in instrs {
                        func.instruction(instr);
                    }
                    func.instruction(&wasm_encoder::Instruction::End);
                }
                Instructions::Arbitrary(body) => {
                    func.raw(body.iter().copied());
                }
            }
            code.function(&func);
        }
        module.section(&code);
    }

    fn encode_data(&self, module: &mut wasm_encoder::Module) {
        if self.data.is_empty() {
            return;
        }
        let mut data = wasm_encoder::DataSection::new();
        for seg in &self.data {
            match &seg.kind {
                DataSegmentKind::Active {
                    memory_index,
                    offset,
                } => {
                    let offset = match *offset {
                        Offset::Const32(n) => ConstExpr::i32_const(n),
                        Offset::Const64(n) => ConstExpr::i64_const(n),
                        Offset::Global(g) => ConstExpr::global_get(g),
                    };
                    data.active(*memory_index, &offset, seg.init.iter().copied());
                }
                DataSegmentKind::Passive => {
                    data.passive(seg.init.iter().copied());
                }
            }
        }
        module.section(&data);
    }
}

pub(crate) fn translate_entity_type(ty: &EntityType) -> wasm_encoder::EntityType {
    match ty {
        EntityType::Tag(t) => wasm_encoder::EntityType::Tag(wasm_encoder::TagType {
            kind: wasm_encoder::TagKind::Exception,
            func_type_idx: t.func_type_idx,
        }),
        EntityType::Func(f, _) => wasm_encoder::EntityType::Function(*f),
        EntityType::Table(ty) => (*ty).into(),
        EntityType::Memory(m) => (*m).into(),
        EntityType::Global(g) => (*g).into(),
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-smith-0.210.0/src/core/terminate.rs

Source (jump to first uncovered line)
use super::*;
use anyhow::{bail, Result};

impl Module {
    /// Ensure that all of this Wasm module's functions will terminate when
    /// executed.
    ///
    /// This adds a new mutable, exported global to the module to keep track of
    /// how much "fuel" is left. Fuel is decremented at the head of each loop
    /// and function. When fuel reaches zero, a trap is raised.
    ///
    /// The index of the fuel global is returned, so that you may control how
    /// much fuel the module is given.
    ///
    /// # Errors
    ///
    /// Returns an error if any function body was generated with
    /// possibly-invalid bytes rather than being generated by wasm-smith. In
    /// such a situation this pass does not parse the input bytes and inject
    /// instructions, instead it returns an error.
    pub fn ensure_termination(&mut self, default_fuel: u32) -> Result<u32> {
        let fuel_global = self.globals.len() as u32;
        self.globals.push(GlobalType {
            val_type: ValType::I32,
            mutable: true,
            shared: false,
        });
        self.defined_globals
            .push((fuel_global, ConstExpr::i32_const(default_fuel as i32)));

        for code in &mut self.code {
            let check_fuel = |insts: &mut Vec<Instruction>| {
                // if fuel == 0 { trap }
                insts.push(Instruction::GlobalGet(fuel_global));
                insts.push(Instruction::I32Eqz);
                insts.push(Instruction::If(BlockType::Empty));
                insts.push(Instruction::Unreachable);
                insts.push(Instruction::End);

                // fuel -= 1
                insts.push(Instruction::GlobalGet(fuel_global));
                insts.push(Instruction::I32Const(1));
                insts.push(Instruction::I32Sub);
                insts.push(Instruction::GlobalSet(fuel_global));
            };

            let instrs = match &mut code.instructions {
                Instructions::Generated(list) => list,
                Instructions::Arbitrary(_) => {
                    bail!(
                        "failed to ensure that a function generated due to it \
                         containing arbitrary instructions"
                    )
                }
            };
            let mut new_insts = Vec::with_capacity(instrs.len() * 2);

            // Check fuel at the start of functions to deal with infinite
            // recursion.
            check_fuel(&mut new_insts);

            for inst in mem::replace(instrs, vec![]) {
                let is_loop = matches!(&inst, Instruction::Loop(_));
                new_insts.push(inst);

                // Check fuel at loop heads to deal with infinite loops.
                if is_loop {
                    check_fuel(&mut new_insts);
                }
            }

            *instrs = new_insts;
        }

        Ok(fuel_global)
    }
}

/Users/hota1024/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wasm-smith-0.210.0/src/lib.rs

Source (jump to first uncovered line)
//! A WebAssembly test case generator.
//!
//! ## Usage
//!
//! First, use [`cargo fuzz`](https://github.com/rust-fuzz/cargo-fuzz) to define
//! a new fuzz target:
//!
//! ```shell
//! $ cargo fuzz add my_wasm_smith_fuzz_target
//! ```
//!
//! Next, add `wasm-smith` to your dependencies:
//!
//! ```shell
//! $ cargo add wasm-smith
//! ```
//!
//! Then, define your fuzz target so that it takes arbitrary
//! `wasm_smith::Module`s as an argument, convert the module into serialized
//! Wasm bytes via the `to_bytes` method, and then feed it into your system:
//!
//! ```no_run
//! // fuzz/fuzz_targets/my_wasm_smith_fuzz_target.rs
//!
//! #![no_main]
//!
//! use libfuzzer_sys::fuzz_target;
//! use wasm_smith::Module;
//!
//! fuzz_target!(|module: Module| {
//!     let wasm_bytes = module.to_bytes();
//!
//!     // Your code here...
//! });
//! ```
//!
//! Finally, start fuzzing:
//!
//! ```shell
//! $ cargo fuzz run my_wasm_smith_fuzz_target
//! ```
//!
//! > **Note:** For a real world example, also check out [the `validate` fuzz
//! > target](https://github.com/fitzgen/wasm-smith/blob/main/fuzz/fuzz_targets/validate.rs)
//! > defined in this repository. Using the `wasmparser` crate, it checks that
//! > every module generated by `wasm-smith` validates successfully.
//!
//! ## Design
//!
//! The design and implementation strategy of wasm-smith is outlined in
//! [this article](https://fitzgeraldnick.com/2020/08/24/writing-a-test-case-generator.html).

#![deny(missing_docs, missing_debug_implementations)]
// Needed for the `instructions!` macro in `src/code_builder.rs`.
#![recursion_limit = "512"]

mod component;
mod config;
mod core;

pub use crate::core::{InstructionKind, InstructionKinds, Module};
use arbitrary::{Result, Unstructured};
pub use component::Component;
pub use config::{Config, MemoryOffsetChoices};
use std::{collections::HashSet, fmt::Write, str};
use wasm_encoder::MemoryType;

#[cfg(feature = "_internal_cli")]
pub use config::InternalOptionalConfig;

pub(crate) fn page_size(mem: &MemoryType) -> u32 {
    const DEFAULT_WASM_PAGE_SIZE: u32 = 65_536;
    mem.page_size_log2.unwrap_or(DEFAULT_WASM_PAGE_SIZE)
}

/// Do something an arbitrary number of times.
///
/// The callback can return `false` to exit the loop early.
pub(crate) fn arbitrary_loop<'a>(
    u: &mut Unstructured<'a>,
    min: usize,
    max: usize,
    mut f: impl FnMut(&mut Unstructured<'a>) -> Result<bool>,
) -> Result<()> {
    assert!(max >= min);
    for _ in 0..min {
        if !f(u)? {
            return Err(arbitrary::Error::IncorrectFormat);
        }
    }
    for _ in 0..(max - min) {
        let keep_going = u.arbitrary().unwrap_or(false);
        if !keep_going {
            break;
        }

        if !f(u)? {
            break;
        }
    }

    Ok(())
}

// Mirror what happens in `Arbitrary for String`, but do so with a clamped size.
pub(crate) fn limited_str<'a>(max_size: usize, u: &mut Unstructured<'a>) -> Result<&'a str> {
    let size = u.arbitrary_len::<u8>()?;
    let size = std::cmp::min(size, max_size);
    match str::from_utf8(u.peek_bytes(size).unwrap()) {
        Ok(s) => {
            u.bytes(size).unwrap();
            Ok(s)
        }
        Err(e) => {
            let i = e.valid_up_to();
            let valid = u.bytes(i).unwrap();
            let s = str::from_utf8(valid).unwrap();
            Ok(s)
        }
    }
}

pub(crate) fn limited_string(max_size: usize, u: &mut Unstructured) -> Result<String> {
    Ok(limited_str(max_size, u)?.into())
}

pub(crate) fn unique_string(
    max_size: usize,
    names: &mut HashSet<String>,
    u: &mut Unstructured,
) -> Result<String> {
    let mut name = limited_string(max_size, u)?;
    while names.contains(&name) {
        write!(&mut name, "{}", names.len()).unwrap();
    }
    names.insert(name.clone());
    Ok(name)
}

pub(crate) fn unique_kebab_string(
    max_size: usize,
    names: &mut HashSet<String>,
    u: &mut Unstructured,
) -> Result<String> {
    let size = std::cmp::min(u.arbitrary_len::<u8>()?, max_size);
    let mut name = String::with_capacity(size);
    let mut require_alpha = true;
    for _ in 0..size {
        name.push(match u.int_in_range::<u8>(0..=36)? {
            x if (0..26).contains(&x) => {
                require_alpha = false;
                (b'a' + x) as char
            }
            x if (26..36).contains(&x) => {
                if require_alpha {
                    require_alpha = false;
                    (b'a' + (x - 26)) as char
                } else {
                    (b'0' + (x - 26)) as char
                }
            }
            x if x == 36 => {
                if require_alpha {
                    require_alpha = false;
                    'a'
                } else {
                    require_alpha = true;
                    '-'
                }
            }
            _ => unreachable!(),
        });
    }

    if name.is_empty() || name.ends_with('-') {
        name.push('a');
    }

    while names.contains(&name) {
        write!(&mut name, "{}", names.len()).unwrap();
    }

    names.insert(name.clone());

    Ok(name)
}

pub(crate) fn unique_url(
    max_size: usize,
    names: &mut HashSet<String>,
    u: &mut Unstructured,
) -> Result<String> {
    let path = unique_kebab_string(max_size, names, u)?;
    Ok(format!("https://example.com/{path}"))
}

/Users/hota1024/GitHub/hota1024/wasmicon/crates/wasm_parser/src/decoder/binary/instructions/block.rs

Source (jump to first uncovered line)
use crate::decoder::binary::types::ValueType;

#[derive(Debug, Clone, PartialEq)]
pub struct Block {
    pub block_type: BlockType,
}

#[derive(Debug, Clone, PartialEq)]
pub enum BlockType {
    Empty,
    Value(Vec<ValueType>),
    TypeIndex(u32),
}

impl BlockType {
    pub fn result_count(&self) -> usize {
        match self {
            Self::Empty => 0,
            Self::Value(types) => types.len(),
            Self::TypeIndex(_) => 1,
        }
    }
}

/Users/hota1024/GitHub/hota1024/wasmicon/crates/wasm_parser/src/decoder/binary/module.rs

Source
use super::{
    section::Code,
    types::{Data, Element, Export, FuncType, Global, Import, MemoryType, TableType},
};

#[derive(Debug, Clone, PartialEq)]
pub struct Module {
    pub version: u32,
    pub custom_section: Option<()>,
    pub type_section: Option<Vec<FuncType>>,
    pub import_section: Option<Vec<Import>>,
    pub function_section: Option<Vec<u32>>,
    pub table_section: Option<Vec<TableType>>,
    pub memory_section: Option<Vec<MemoryType>>,
    pub global_section: Option<Vec<Global>>,
    pub export_section: Option<Vec<Export>>,
    pub start_section: Option<u32>,
    pub element_section: Option<Vec<Element>>,
    pub code_section: Option<Vec<Code>>,
    pub data_section: Option<Vec<Data>>,
    pub data_count_section: Option<u32>,
}

impl Default for Module {
    fn default() -> Self {
        Module {
            version: 0,
            custom_section: None,
            type_section: None,
            import_section: None,
            function_section: None,
            table_section: None,
            memory_section: None,
            global_section: None,
            export_section: None,
            start_section: None,
            element_section: None,
            code_section: None,
            data_section: None,
            data_count_section: None,
        }
    }
}

/Users/hota1024/GitHub/hota1024/wasmicon/crates/wasm_parser/src/decoder/binary/section/id.rs

Source (jump to first uncovered line)
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub enum SectionId {
    Custom,
    Type,
    Import,
    Function,
    Table,
    Memory,
    Global,
    Export,
    Start,
    Element,
    Code,
    Data,
    DataCount,
    Unknown(u8),
}

impl From<u8> for SectionId {
    fn from(value: u8) -> Self {
        match value {
            0 => SectionId::Custom,
            1 => SectionId::Type,
            2 => SectionId::Import,
            3 => SectionId::Function,
            4 => SectionId::Table,
            5 => SectionId::Memory,
            6 => SectionId::Global,
            7 => SectionId::Export,
            8 => SectionId::Start,
            9 => SectionId::Element,
            10 => SectionId::Code,
            11 => SectionId::Data,
            12 => SectionId::DataCount,
            _ => SectionId::Unknown(value),
        }
    }
}

impl SectionId {
    pub fn is_unknown(&self) -> bool {
        match self {
            SectionId::Unknown(_) => true,
            _ => false,
        }
    }
}

/Users/hota1024/GitHub/hota1024/wasmicon/crates/wasm_parser/src/decoder/decoder.rs

Source (jump to first uncovered line)
use anyhow::{bail, Context};
use std::io::{BufReader, Read};

use crate::decoder::binary::types::ValueType;

use super::{
    binary::{
        instructions::{Block, BlockType, Instruction, MemArg},
        module::Module,
        section::{Code, SectionId},
        types::{
            Element, ElementMode, Export, ExportDesc, FuncType, Global, GlobalType, Import,
            ImportDesc, Limits, MemoryType, RefType, TableType,
        },
    },
    result::{DecodeError, Result},
    types::{Data, DataMode},
};

pub struct Decoder<R> {
    reader: BufReader<R>,
}

impl<R: Read> Decoder<R> {
    pub fn new(reader: R) -> Self {
        Decoder {
            reader: BufReader::new(reader),
        }
    }

    fn is_empty(&mut self) -> bool {
        // self.reader.fill_buf().unwrap().is_empty()
        self.reader.buffer().is_empty()
    }

    pub fn decode(&mut self) -> Result<Module> {
        self.validate_magic_header()?;
        let version = self.decode_version()?;

        if version != 1 {
            bail!(DecodeError::InvalidVersion);
        }

        let mut module = Module::default();

        loop {
            if self.is_empty() {
                break;
            }

            let id = match self.read_section() {
                Ok((id, _)) => id,
                Err(e) => return Err(e),
            };

            match id {
                SectionId::Custom => {}
                SectionId::Type => {
                    module.type_section =
                        Some(self.decode_type_section().context("decode type section")?);
                }
                SectionId::Import => {
                    module.import_section = Some(
                        self.decode_import_section()
                            .context("decode import section")?,
                    );
                }
                SectionId::Function => {
                    module.function_section = Some(
                        self.decode_function_section()
                            .context("decode function section")?,
                    );
                }
                SectionId::Table => {
                    module.table_section = Some(
                        self.decode_table_section()
                            .context("decode table section")?,
                    );
                }
                SectionId::Memory => {
                    module.memory_section = Some(
                        self.decode_memory_section()
                            .context("decode memory section")?,
                    );
                }
                SectionId::Global => {
                    module.global_section = Some(
                        self.decode_global_section()
                            .context("decode global section")?,
                    );
                }
                SectionId::Export => {
                    module.export_section = Some(
                        self.decode_export_section()
                            .context("decode export section")?,
                    );
                }
                SectionId::Start => {
                    module.start_section = self
                        .decode_start_section()
                        .context("decode start section")?;
                }
                SectionId::Element => {
                    module.element_section = Some(
                        self.decode_element_section()
                            .context("decode element section")?,
                    );
                }
                SectionId::Code => {
                    module.code_section =
                        Some(self.decode_code_section().context("decode code section")?);
                }
                SectionId::Data => {
                    module.data_section =
                        Some(self.decode_data_section().context("decode data section")?);
                }
                SectionId::DataCount => {
                    module.data_count_section = Some(
                        self.decode_data_count_section()
                            .context("decode data count section")?,
                    );
                }
                _ => {
                    unimplemented!("[decode] {:?} is not implemented", id)
                }
            }
        }

        Ok(module)
    }

    fn validate_magic_header(&mut self) -> Result<()> {
        let mut magic = [0; 4];
        self.reader.read_exact(&mut magic).unwrap();

        match magic {
            [0x00, 0x61, 0x73, 0x6d] => Ok(()),
            _ => bail!(DecodeError::InvalidMagicHeader),
        }
    }

    fn decode_version(&mut self) -> Result<u32> {
        let mut version = [0; 4];
        self.reader.read_exact(&mut version).unwrap();

        Ok(u32::from_le_bytes(version))
    }

    fn decode_type_section(&mut self) -> Result<Vec<FuncType>> {
        self.read_vec(|d| {
            let kind = d.read_u8()?;

            // functype starts with `0x60`.
            // Ref: https://webassembly.github.io/spec/core/binary/types.html#function-types
            if kind != 0x60 {
                bail!(DecodeError::InvalidTypeKind);
            }

            let params = d.read_vec(|d| d.read_value_type()).context("read params")?;

            let results = d
                .read_vec(|d| d.read_value_type())
                .context("read results")?;

            Ok(FuncType { params, results })
        })
        .context("read type section vector")
    }

    fn decode_import_section(&mut self) -> Result<Vec<Import>> {
        self.read_vec(|d| {
            let module = d.read_name()?;
            let field = d.read_name()?;
            let desc_id = d.read_u8()?;

            let desc = match desc_id {
                0x00 => {
                    let type_index = d.read_size()?;
                    ImportDesc::Func(type_index)
                }
                0x01 => {
                    let type_index = d.read_table_type()?;
                    ImportDesc::Table(type_index)
                }
                0x02 => {
                    let limits = d.read_limits()?;
                    ImportDesc::Memory(limits)
                }
                0x03 => {
                    let global = d.read_global_type()?;
                    ImportDesc::Global(global)
                }
                id => bail!(DecodeError::InvalidImportDescription(id)),
            };

            Ok(Import {
                module,
                field,
                desc,
            })
        })
    }

    fn decode_function_section(&mut self) -> Result<Vec<u32>> {
        self.read_vec(|d| d.read_size())
    }

    fn decode_table_section(&mut self) -> Result<Vec<TableType>> {
        self.read_vec(|d| {
            Ok(TableType {
                element_type: d.read_reference_type()?,
                limits: d.read_limits()?,
            })
        })
    }

    fn decode_memory_section(&mut self) -> Result<Vec<MemoryType>> {
        self.read_vec(|d| {
            Ok(MemoryType {
                limits: d.read_limits()?,
            })
        })
    }

    fn decode_global_section(&mut self) -> Result<Vec<Global>> {
        self.read_vec(|d| {
            let value_type = d.read_value_type()?;
            let mutable = d.read_u8()? == 0x01;

            let init_expr = d.read_instruction_and_end()?;

            Ok(Global {
                global_type: GlobalType {
                    value_type,
                    mutable,
                },
                init_expr,
            })
        })
    }

    fn decode_export_section(&mut self) -> Result<Vec<Export>> {
        self.read_vec(|d| {
            let name = d.read_name()?;
            let desc_kind = d.read_u8()?;

            let desc = match desc_kind {
                0x00 => ExportDesc::Func(d.read_size()?),
                0x01 => ExportDesc::Table(d.read_size()?),
                0x02 => ExportDesc::Mem(d.read_size()?),
                0x03 => ExportDesc::Global(d.read_size()?),
                _ => bail!(DecodeError::InvalidExportDescription),
            };

            Ok(Export { name, desc })
        })
    }

    fn decode_start_section(&mut self) -> Result<Option<u32>> {
        let index = self.read_size()?;
        Ok(Some(index))
    }

    fn decode_element_section(&mut self) -> Result<Vec<Element>> {
        self.read_vec(|d| {
            let prefix = d.read_size()?;

            let element = match prefix {
                0 => {
                    let offset = d.read_instruction_and_end()?;
                    let init = d.read_vec(|d| d.read_size())?;

                    Element {
                        ref_type: RefType::FuncRef,
                        init,
                        mode: ElementMode::Active {
                            table_index: 0,
                            offset,
                        },
                    }
                }
                _ => bail!(DecodeError::UnsupportedElementPrefix),
            };

            Ok(element)
        })
    }

    fn decode_code_section(&mut self) -> Result<Vec<Code>> {
        self.read_vec(|d| {
            let body_size = d.read_size()?;
            let bytes = d.read_bytes(body_size as usize)?;
            let mut d = Decoder::new(bytes.as_slice());

            let locals: Vec<ValueType> = d
                .read_vec(|d| {
                    let mut locals = vec![];
                    let local_count = d.read_size()?;
                    let ty = d.read_value_type()?;

                    for _ in 0..local_count {
                        locals.push(ty.clone());
                    }

                    Ok(locals)
                })?
                .into_iter()
                .flatten()
                .collect();

            let body = d.read_instructions()?;

            Ok(Code { locals, code: body })
        })
    }

    fn decode_data_section(&mut self) -> Result<Vec<Data>> {
        self.read_vec(|d| {
            let prefix = d.read_size()?;

            let data = match prefix {
                0 => {
                    let expr = d.read_instruction_and_end()?;
                    let size = d.read_size()?;
                    let bytes = d.read_bytes(size as usize)?;

                    Data {
                        bytes,
                        mode: DataMode::Active {
                            memory_index: 0,
                            offset: expr,
                        },
                    }
                }
                p => bail!(DecodeError::UnsupportedDataPrefix(p)),
            };

            Ok(data)
        })
    }

    fn decode_data_count_section(&mut self) -> Result<u32> {
        self.read_size()
    }

    fn read_instructions(&mut self) -> Result<Vec<Instruction>> {
        let mut instructions = Vec::new();

        loop {
            if self.is_empty() {
                break;
            }

            let instr = self.read_instruction()?;

            instructions.push(instr);
        }

        Ok(instructions)
    }

    fn read_instruction(&mut self) -> Result<Instruction> {
        let opcode = match self.read_u8() {
            Ok(opcode) => opcode,
            Err(err) => {
                return Err(err);
            }
        };

        let instr = match opcode {
            // control instructions
            0x00 => Instruction::Unreachable,
            0x01 => Instruction::Nop,
            0x02 => Instruction::Block {
                block: Block {
                    block_type: self.read_block_type().context("instruction block")?,
                },
            },
            0x03 => Instruction::Loop {
                block: Block {
                    block_type: self.read_block_type().context("instruction loop block")?,
                },
            },
            0x04 => Instruction::If {
                block: Block {
                    block_type: self.read_block_type().context("instruction if block")?,
                },
            },
            0x05 => Instruction::Else,
            0x0B => Instruction::End,
            0x0C => Instruction::Br {
                level: self.read_size()?,
            },
            0x0D => Instruction::BrIf {
                level: self.read_size()?,
            },
            0xE => Instruction::BrTable {
                label_indexes: self.read_vec(|d| d.read_size())?,
                default_index: self.read_size()?,
            },
            0x0F => Instruction::Return,
            0x10 => Instruction::Call {
                func_index: self.read_size()?,
            },
            0x11 => Instruction::CallIndirect {
                type_index: self.read_size()?,
                table_index: self.read_size()?,
            },
            // reference instructions
            0xD0 => Instruction::RefNull {
                ref_type: self.read_reference_type()?,
            },
            0xD1 => Instruction::RefIsNull,
            0xD2 => Instruction::RefFunc {
                func_index: self.read_size()?,
            },
            // parametric instructions
            0x1A => Instruction::Drop,
            0x1B => Instruction::Select { result_types: None },
            0x1C => Instruction::Select {
                result_types: Some(self.read_vec(|d| d.read_value_type())?),
            },
            // variable instructions
            0x20 => Instruction::LocalGet {
                local_index: self.read_size()?,
            },
            0x21 => Instruction::LocalSet {
                local_index: self.read_size()?,
            },
            0x22 => Instruction::LocalTee {
                local_index: self.read_size()?,
            },
            0x23 => Instruction::GlobalGet {
                global_index: self.read_size()?,
            },
            0x24 => Instruction::GlobalSet {
                global_index: self.read_size()?,
            },
            // table instructions
            0x25 => Instruction::TableGet {
                table_index: self.read_size()?,
            },
            0x26 => Instruction::TableSet {
                table_index: self.read_size()?,
            },
            0xFC => {
                let id = self.read_size()?;

                match id {
                    0x00 => Instruction::I32TruncSatF32S,
                    0x01 => Instruction::I32TruncSatF32U,
                    0x02 => Instruction::I32TruncSatF64S,
                    0x03 => Instruction::I32TruncSatF64U,
                    0x04 => Instruction::I64TruncSatF32S,
                    0x05 => Instruction::I64TruncSatF32U,
                    0x06 => Instruction::I64TruncSatF64S,
                    0x07 => Instruction::I64TruncSatF64U,
                    0x08 => {
                        let inst = Instruction::MemoryInit {
                            data_index: self.read_size()?,
                        };

                        self.read_u8()?; // 0x00

                        inst
                    }
                    0x09 => Instruction::DataDrop {
                        data_index: self.read_size()?,
                    },
                    0x0A => {
                        let inst = Instruction::MemoryCopy;

                        self.read_u8()?; // 0x00
                        self.read_u8()?; // 0x00

                        inst
                    }
                    0x0B => {
                        let inst = Instruction::MemoryFill;

                        self.read_u8()?; // 0x00

                        inst
                    }
                    0x0C => Instruction::TableInit {
                        element_index: self.read_size()?,
                        table_index: self.read_size()?,
                    },
                    0x0D => Instruction::ElemDrop {
                        element_index: self.read_size()?,
                    },
                    0x0E => Instruction::TableCopy {
                        dst_table_index: self.read_size()?,
                        src_table_index: self.read_size()?,
                    },
                    0x0F => Instruction::TableGrow {
                        table_index: self.read_size()?,
                    },
                    0x10 => Instruction::TableSize {
                        table_index: self.read_size()?,
                    },
                    0x11 => Instruction::TableFill {
                        table_index: self.read_size()?,
                    },
                    v => bail!(DecodeError::InvalidSubInstructionId(v)),
                }
            }
            // memory instructions
            0x28 => Instruction::I32Load {
                mem_arg: self.read_mem_arg()?,
            },
            0x29 => Instruction::I64Load {
                mem_arg: self.read_mem_arg()?,
            },
            0x2A => Instruction::F32Load {
                mem_arg: self.read_mem_arg()?,
            },
            0x2B => Instruction::F64Load {
                mem_arg: self.read_mem_arg()?,
            },
            0x2C => Instruction::I32Load8S {
                mem_arg: self.read_mem_arg()?,
            },
            0x2D => Instruction::I32Load8U {
                mem_arg: self.read_mem_arg()?,
            },
            0x2E => Instruction::I32Load16S {
                mem_arg: self.read_mem_arg()?,
            },
            0x2F => Instruction::I32Load16U {
                mem_arg: self.read_mem_arg()?,
            },
            0x30 => Instruction::I64Load8S {
                mem_arg: self.read_mem_arg()?,
            },
            0x31 => Instruction::I64Load8U {
                mem_arg: self.read_mem_arg()?,
            },
            0x32 => Instruction::I64Load16S {
                mem_arg: self.read_mem_arg()?,
            },
            0x33 => Instruction::I64Load16U {
                mem_arg: self.read_mem_arg()?,
            },
            0x34 => Instruction::I64Load32S {
                mem_arg: self.read_mem_arg()?,
            },
            0x35 => Instruction::I64Load32U {
                mem_arg: self.read_mem_arg()?,
            },
            0x36 => Instruction::I32Store {
                mem_arg: self.read_mem_arg()?,
            },
            0x37 => Instruction::I64Store {
                mem_arg: self.read_mem_arg()?,
            },
            0x38 => Instruction::F32Store {
                mem_arg: self.read_mem_arg()?,
            },
            0x39 => Instruction::F64Store {
                mem_arg: self.read_mem_arg()?,
            },
            0x3A => Instruction::I32Store8 {
                mem_arg: self.read_mem_arg()?,
            },
            0x3B => Instruction::I32Store16 {
                mem_arg: self.read_mem_arg()?,
            },
            0x3C => Instruction::I64Store8 {
                mem_arg: self.read_mem_arg()?,
            },
            0x3D => Instruction::I64Store16 {
                mem_arg: self.read_mem_arg()?,
            },
            0x3E => Instruction::I64Store32 {
                mem_arg: self.read_mem_arg()?,
            },
            0x3F => {
                self.read_u8()?;
                Instruction::MemorySize
            }
            0x40 => {
                self.read_u8()?;
                Instruction::MemoryGrow
            }
            /* numerics */
            0x41 => Instruction::I32Const {
                value: self.read_i32()?,
            },
            0x42 => Instruction::I64Const {
                value: self.read_i64()?,
            },
            0x43 => Instruction::F32Const {
                value: self.read_f32()?,
            },
            0x44 => Instruction::F64Const {
                value: self.read_f64()?,
            },
            0x45 => Instruction::I32Eqz,
            0x46 => Instruction::I32Eq,
            0x47 => Instruction::I32Ne,
            0x48 => Instruction::I32LtS,
            0x49 => Instruction::I32LtU,
            0x4A => Instruction::I32GtS,
            0x4B => Instruction::I32GtU,
            0x4C => Instruction::I32LeS,
            0x4D => Instruction::I32LeU,
            0x4E => Instruction::I32GeS,
            0x4F => Instruction::I32GeU,
            0x50 => Instruction::I64Eqz,
            0x51 => Instruction::I64Eq,
            0x52 => Instruction::I64Ne,
            0x53 => Instruction::I64LtS,
            0x54 => Instruction::I64LtU,
            0x55 => Instruction::I64GtS,
            0x56 => Instruction::I64GtU,
            0x57 => Instruction::I64LeS,
            0x58 => Instruction::I64LeU,
            0x59 => Instruction::I64GeS,
            0x5A => Instruction::I64GeU,
            0x5B => Instruction::F32Eq,
            0x5C => Instruction::F32Ne,
            0x5D => Instruction::F32Lt,
            0x5E => Instruction::F32Gt,
            0x5F => Instruction::F32Le,
            0x60 => Instruction::F32Ge,
            0x61 => Instruction::F64Eq,
            0x62 => Instruction::F64Ne,
            0x63 => Instruction::F64Lt,
            0x64 => Instruction::F64Gt,
            0x65 => Instruction::F64Le,
            0x66 => Instruction::F64Ge,
            0x67 => Instruction::I32Clz,
            0x68 => Instruction::I32Ctz,
            0x69 => Instruction::I32Popcnt,
            0x6A => Instruction::I32Add,
            0x6B => Instruction::I32Sub,
            0x6C => Instruction::I32Mul,
            0x6D => Instruction::I32DivS,
            0x6E => Instruction::I32DivU,
            0x6F => Instruction::I32RemS,
            0x70 => Instruction::I32RemU,
            0x71 => Instruction::I32And,
            0x72 => Instruction::I32Or,
            0x73 => Instruction::I32Xor,
            0x74 => Instruction::I32Shl,
            0x75 => Instruction::I32ShrS,
            0x76 => Instruction::I32ShrU,
            0x77 => Instruction::I32Rotl,
            0x78 => Instruction::I32Rotr,
            0x79 => Instruction::I64Clz,
            0x7A => Instruction::I64Ctz,
            0x7B => Instruction::I64Popcnt,
            0x7C => Instruction::I64Add,
            0x7D => Instruction::I64Sub,
            0x7E => Instruction::I64Mul,
            0x7F => Instruction::I64DivS,
            0x80 => Instruction::I64DivU,
            0x81 => Instruction::I64RemS,
            0x82 => Instruction::I64RemU,
            0x83 => Instruction::I64And,
            0x84 => Instruction::I64Or,
            0x85 => Instruction::I64Xor,
            0x86 => Instruction::I64Shl,
            0x87 => Instruction::I64ShrS,
            0x88 => Instruction::I64ShrU,
            0x89 => Instruction::I64Rotl,
            0x8A => Instruction::I64Rotr,
            0x8B => Instruction::F32Abs,
            0x8C => Instruction::F32Neg,
            0x8D => Instruction::F32Ceil,
            0x8E => Instruction::F32Floor,
            0x8F => Instruction::F32Trunc,
            0x90 => Instruction::F32Nearest,
            0x91 => Instruction::F32Sqrt,
            0x92 => Instruction::F32Add,
            0x93 => Instruction::F32Sub,
            0x94 => Instruction::F32Mul,
            0x95 => Instruction::F32Div,
            0x96 => Instruction::F32Min,
            0x97 => Instruction::F32Max,
            0x98 => Instruction::F32Copysign,
            0x99 => Instruction::F64Abs,
            0x9A => Instruction::F64Neg,
            0x9B => Instruction::F64Ceil,
            0x9C => Instruction::F64Floor,
            0x9D => Instruction::F64Trunc,
            0x9E => Instruction::F64Nearest,
            0x9F => Instruction::F64Sqrt,
            0xA0 => Instruction::F64Add,
            0xA1 => Instruction::F64Sub,
            0xA2 => Instruction::F64Mul,
            0xA3 => Instruction::F64Div,
            0xA4 => Instruction::F64Min,
            0xA5 => Instruction::F64Max,
            0xA6 => Instruction::F64Copysign,
            0xA7 => Instruction::I32WrapI64,
            0xA8 => Instruction::I32TruncF32S,
            0xA9 => Instruction::I32TruncF32U,
            0xAA => Instruction::I32TruncF64S,
            0xAB => Instruction::I32TruncF64U,
            0xAC => Instruction::I64ExtendI32S,
            0xAD => Instruction::I64ExtendI32U,
            0xAE => Instruction::I64TruncF32S,
            0xAF => Instruction::I64TruncF32U,
            0xB0 => Instruction::I64TruncF64S,
            0xB1 => Instruction::I64TruncF64U,
            0xB2 => Instruction::F32ConvertI32S,
            0xB3 => Instruction::F32ConvertI32U,
            0xB4 => Instruction::F32ConvertI64S,
            0xB5 => Instruction::F32ConvertI64U,
            0xB6 => Instruction::F32DemoteF64,
            0xB7 => Instruction::F64ConvertI32S,
            0xB8 => Instruction::F64ConvertI32U,
            0xB9 => Instruction::F64ConvertI64S,
            0xBA => Instruction::F64ConvertI64U,
            0xBB => Instruction::F64PromoteF32,
            0xBC => Instruction::I32ReinterpretF32,
            0xBD => Instruction::I64ReinterpretF64,
            0xBE => Instruction::F32ReinterpretI32,
            0xBF => Instruction::F64ReinterpretI64,
            0xC0 => Instruction::I32Extend8S,
            0xC1 => Instruction::I32Extend16S,
            0xC2 => Instruction::I64Extend8S,
            0xC3 => Instruction::I64Extend16S,
            0xC4 => Instruction::I64Extend32S,
            _ => unimplemented!("Opcode 0x{:02x} is not implemented", opcode),
        };

        Ok(instr)
    }

    fn read_instruction_and_end(&mut self) -> Result<Instruction> {
        let instr = self.read_instruction()?;
        let end = self.read_size()?;
        if end != 0x0B {
            bail!(DecodeError::Expected("0x0B".to_owned()));
        }

        Ok(instr)
    }

    fn read_vec<T>(&mut self, decode_fn: impl Fn(&mut Self) -> Result<T>) -> Result<Vec<T>> {
        let size = self.read_size()?;
        let mut items = Vec::with_capacity(size as usize);

        for _ in 0..size {
            items.push(decode_fn(self)?);
        }

        Ok(items)
    }

    fn read_u8(&mut self) -> Result<u8> {
        let mut buf = [0; 1];
        let result = self.reader.read_exact(&mut buf);

        match result {
            Ok(_) => Ok(buf[0]),
            Err(_) => bail!(DecodeError::Expected("u8".to_owned())),
        }
    }

    fn read_i32(&mut self) -> Result<i32> {
        let size_result = leb128::read::signed(&mut self.reader);

        match size_result {
            Ok(size) => Ok(size as i32),
            Err(_) => bail!(DecodeError::Expected("i32".to_owned())),
        }
    }

    fn read_i64(&mut self) -> Result<i64> {
        let size_result = leb128::read::signed(&mut self.reader);

        match size_result {
            Ok(size) => Ok(size),
            Err(_) => bail!(DecodeError::Expected("i64".to_owned())),
        }
    }

    fn read_f32(&mut self) -> Result<f32> {
        let mut buf = [0; 4];
        let result = self.reader.read_exact(&mut buf);

        match result {
            Ok(_) => Ok(f32::from_le_bytes(buf)),
            Err(_) => bail!(DecodeError::Expected("f32".to_owned())),
        }
    }

    fn read_f64(&mut self) -> Result<f64> {
        let mut buf = [0; 8];
        let result = self.reader.read_exact(&mut buf);

        match result {
            Ok(_) => Ok(f64::from_le_bytes(buf)),
            Err(_) => bail!(DecodeError::Expected("f64".to_owned())),
        }
    }

    fn read_section(&mut self) -> Result<(SectionId, u32)> {
        let id = self.read_u8().context("read section id")?;
        let id = SectionId::from(id);
        if id.is_unknown() {
            bail!(DecodeError::InvalidSectionId(id));
        }

        let size = self.read_size().context("read section size")?;

        Ok((id, size))
    }

    fn read_size(&mut self) -> Result<u32> {
        let size_result = leb128::read::unsigned(&mut self.reader);

        match size_result {
            Ok(size) => Ok(size as u32),
            Err(_) => bail!(DecodeError::Expected("size(leb128 unsigned)".to_owned())),
        }
    }

    fn read_bytes(&mut self, size: usize) -> Result<Vec<u8>> {
        let mut bytes = vec![0; size];
        let result = self.reader.read_exact(&mut bytes);

        match result {
            Ok(_) => Ok(bytes),
            Err(_) => bail!(DecodeError::Expected(format!("{} bytes", size))),
        }
    }

    fn read_mem_arg(&mut self) -> Result<MemArg> {
        Ok(MemArg {
            align: self.read_size()?,
            offset: self.read_size()?,
        })
    }

    fn read_reference_type(&mut self) -> Result<RefType> {
        let type_id = self.read_u8()?;

        match type_id {
            0x70 => Ok(RefType::FuncRef),
            0x6F => Ok(RefType::ExternRef),
            _ => bail!(DecodeError::InvalidRefType),
        }
    }

    fn read_block_type(&mut self) -> Result<BlockType> {
        match self.read_value_type() {
            Ok(value_type) => Ok(BlockType::Value(vec![value_type])),
            Err(err) => match err.downcast_ref::<DecodeError>() {
                Some(err) => {
                    if let DecodeError::InvalidValueType(v) = err {
                        if *v == 0x40 {
                            Ok(BlockType::Empty)
                        } else {
                            Ok(BlockType::TypeIndex((*v).into()))
                        }
                    } else {
                        Err(err.clone().into())
                    }
                }
                None => Err(err),
            },
        }
    }

    fn read_value_type(&mut self) -> Result<ValueType> {
        let type_id = self.read_u8()?;

        let ty = match type_id {
            0x7F => ValueType::I32,
            0x7E => ValueType::I64,
            0x7D => ValueType::F32,
            0x7C => ValueType::F64,
            0x7B => ValueType::V128,
            0x70 => ValueType::FuncRef,
            0x6F => ValueType::ExternRef,
            v => bail!(DecodeError::InvalidValueType(v)),
        };

        Ok(ty)
    }

    fn read_limits(&mut self) -> Result<Limits> {
        match self.read_u8()? {
            0x00 => Ok(Limits {
                min: self.read_size()?,
                max: None,
            }),
            0x01 => Ok(Limits {
                min: self.read_size()?,
                max: Some(self.read_size()?),
            }),
            _ => bail!(DecodeError::InvalidLimitsKind),
        }
    }

    fn read_name(&mut self) -> Result<String> {
        let size = self.read_size()?;
        let mut buf = vec![0; size as usize];
        let result = self.reader.read_exact(&mut buf);

        match result {
            Ok(_) => Ok(String::from_utf8(buf).unwrap()),
            Err(_) => bail!(DecodeError::Expected("name".to_owned())),
        }
    }

    fn read_global_type(&mut self) -> Result<GlobalType> {
        let value_type = self.read_value_type()?;
        let mutable = self.read_u8()? == 0x01;

        Ok(GlobalType {
            value_type,
            mutable,
        })
    }

    fn read_table_type(&mut self) -> Result<TableType> {
        let element_type = self.read_reference_type()?;
        let limits = self.read_limits()?;

        Ok(TableType {
            element_type,
            limits,
        })
    }
}

Line	Count	Source (jump to first uncovered line)
1		#[cfg(std_backtrace)]
2		pub(crate) use std::backtrace::{Backtrace, BacktraceStatus};
3
4		#[cfg(all(not(std_backtrace), feature = "backtrace"))]
5		pub(crate) use self::capture::{Backtrace, BacktraceStatus};
6
7		#[cfg(not(any(std_backtrace, feature = "backtrace")))]
8		pub(crate) enum Backtrace {}
9
10		#[cfg(std_backtrace)]
11		macro_rules! impl_backtrace {
12		() => {
13		std::backtrace::Backtrace
14		};
15		}
16
17		#[cfg(all(not(std_backtrace), feature = "backtrace"))]
18		macro_rules! impl_backtrace {
19		() => {
20		impl core::fmt::Debug + core::fmt::Display
21		};
22		}
23
24		#[cfg(any(std_backtrace, feature = "backtrace"))]
25		macro_rules! backtrace {
26		() => {
27		Some(crate::backtrace::Backtrace::capture())
28		};
29		}
30
31		#[cfg(not(any(std_backtrace, feature = "backtrace")))]
32		macro_rules! backtrace {
33		() => {
34		None
35		};
36		}
37
38		#[cfg(error_generic_member_access)]
39		macro_rules! backtrace_if_absent {
40		($err:expr) => {
41		match std::error::request_ref::<std::backtrace::Backtrace>($err as &dyn std::error::Error) {
42		Some(_) => None,
43		None => backtrace!(),
44		}
45		};
46		}
47
48		#[cfg(all(
49		feature = "std",
50		not(error_generic_member_access),
51		any(std_backtrace, feature = "backtrace")
52		))]
53		macro_rules! backtrace_if_absent {
54		($err:expr) => {
55		backtrace!()
56		};
57		}
58
59		#[cfg(all(feature = "std", not(std_backtrace), not(feature = "backtrace")))]
60		macro_rules! backtrace_if_absent {
61		($err:expr) => {
62		None
63		};
64		}
65
66		#[cfg(all(not(std_backtrace), feature = "backtrace"))]
67		mod capture {
68		use alloc::borrow::{Cow, ToOwned as _};
69		use alloc::vec::Vec;
70		use backtrace::{BacktraceFmt, BytesOrWideString, Frame, PrintFmt, SymbolName};
71		use core::cell::UnsafeCell;
72		use core::fmt::{self, Debug, Display};
73		use core::sync::atomic::{AtomicUsize, Ordering};
74		use std::env;
75		use std::path::{self, Path, PathBuf};
76		use std::sync::Once;
77
78		pub(crate) struct Backtrace {
79		inner: Inner,
80		}
81
82		pub(crate) enum BacktraceStatus {
83		Unsupported,
84		Disabled,
85		Captured,
86		}
87
88		enum Inner {
89		Unsupported,
90		Disabled,
91		Captured(LazilyResolvedCapture),
92		}
93
94		struct Capture {
95		actual_start: usize,
96		resolved: bool,
97		frames: Vec<BacktraceFrame>,
98		}
99
100		struct BacktraceFrame {
101		frame: Frame,
102		symbols: Vec<BacktraceSymbol>,
103		}
104
105		struct BacktraceSymbol {
106		name: Option<Vec<u8>>,
107		filename: Option<BytesOrWide>,
108		lineno: Option<u32>,
109		colno: Option<u32>,
110		}
111
112		enum BytesOrWide {
113		Bytes(Vec<u8>),
114		Wide(Vec<u16>),
115		}
116
117		impl Debug for Backtrace {
118		fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
119		let capture = match &self.inner {
120		Inner::Unsupported => return fmt.write_str("<unsupported>"),
121		Inner::Disabled => return fmt.write_str("<disabled>"),
122		Inner::Captured(c) => c.force(),
123		};
124
125		let frames = &capture.frames[capture.actual_start..];
126
127		write!(fmt, "Backtrace ")?;
128
129		let mut dbg = fmt.debug_list();
130
131		for frame in frames {
132		if frame.frame.ip().is_null() {
133		continue;
134		}
135
136		dbg.entries(&frame.symbols);
137		}
138
139		dbg.finish()
140		}
141		}
142
143		impl Debug for BacktraceFrame {
144		fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
145		let mut dbg = fmt.debug_list();
146		dbg.entries(&self.symbols);
147		dbg.finish()
148		}
149		}
150
151		impl Debug for BacktraceSymbol {
152		fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
153		write!(fmt, "{{ ")?;
154
155		if let Some(fn_name) = self.name.as_ref().map(\|b\| SymbolName::new(b)) {
156		write!(fmt, "fn: \"{:#}\"", fn_name)?;
157		} else {
158		write!(fmt, "fn: <unknown>")?;
159		}
160
161		if let Some(fname) = self.filename.as_ref() {
162		write!(fmt, ", file: \"{:?}\"", fname)?;
163		}
164
165		if let Some(line) = self.lineno {
166		write!(fmt, ", line: {:?}", line)?;
167		}
168
169		write!(fmt, " }}")
170		}
171		}
172
173		impl Debug for BytesOrWide {
174		fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
175		output_filename(
176		fmt,
177		match self {
178		BytesOrWide::Bytes(w) => BytesOrWideString::Bytes(w),
179		BytesOrWide::Wide(w) => BytesOrWideString::Wide(w),
180		},
181		PrintFmt::Short,
182		env::current_dir().as_ref().ok(),
183		)
184		}
185		}
186
187		impl Backtrace {
188		fn enabled() -> bool {
189		static ENABLED: AtomicUsize = AtomicUsize::new(0);
190		match ENABLED.load(Ordering::Relaxed) {
191		0 => {}
192		1 => return false,
193		_ => return true,
194		}
195		let enabled = match env::var_os("RUST_LIB_BACKTRACE") {
196		Some(s) => s != "0",
197		None => match env::var_os("RUST_BACKTRACE") {
198		Some(s) => s != "0",
199		None => false,
200		},
201		};
202		ENABLED.store(enabled as usize + 1, Ordering::Relaxed);
203		enabled
204		}
205
206		#[inline(never)] // want to make sure there's a frame here to remove
207		pub(crate) fn capture() -> Backtrace {
208		if Backtrace::enabled() {
209		Backtrace::create(Backtrace::capture as usize)
210		} else {
211		let inner = Inner::Disabled;
212		Backtrace { inner }
213		}
214		}
215
216		// Capture a backtrace which starts just before the function addressed
217		// by `ip`
218		fn create(ip: usize) -> Backtrace {
219		let mut frames = Vec::new();
220		let mut actual_start = None;
221		backtrace::trace(\|frame\| {
222		frames.push(BacktraceFrame {
223		frame: frame.clone(),
224		symbols: Vec::new(),
225		});
226		if frame.symbol_address() as usize == ip && actual_start.is_none() {
227		actual_start = Some(frames.len() + 1);
228		}
229		true
230		});
231
232		// If no frames came out assume that this is an unsupported platform
233		// since `backtrace` doesn't provide a way of learning this right
234		// now, and this should be a good enough approximation.
235		let inner = if frames.is_empty() {
236		Inner::Unsupported
237		} else {
238		Inner::Captured(LazilyResolvedCapture::new(Capture {
239		actual_start: actual_start.unwrap_or(0),
240		frames,
241		resolved: false,
242		}))
243		};
244
245		Backtrace { inner }
246		}
247
248		pub(crate) fn status(&self) -> BacktraceStatus {
249		match self.inner {
250		Inner::Unsupported => BacktraceStatus::Unsupported,
251		Inner::Disabled => BacktraceStatus::Disabled,
252		Inner::Captured(_) => BacktraceStatus::Captured,
253		}
254		}
255		}
256
257		impl Display for Backtrace {
258		fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
259		let capture = match &self.inner {
260		Inner::Unsupported => return fmt.write_str("unsupported backtrace"),
261		Inner::Disabled => return fmt.write_str("disabled backtrace"),
262		Inner::Captured(c) => c.force(),
263		};
264
265		let full = fmt.alternate();
266		let (frames, style) = if full {
267		(&capture.frames[..], PrintFmt::Full)
268		} else {
269		(&capture.frames[capture.actual_start..], PrintFmt::Short)
270		};
271
272		// When printing paths we try to strip the cwd if it exists,
273		// otherwise we just print the path as-is. Note that we also only do
274		// this for the short format, because if it's full we presumably
275		// want to print everything.
276		let cwd = env::current_dir();
277		let mut print_path = move \|fmt: &mut fmt::Formatter, path: BytesOrWideString\| {
278		output_filename(fmt, path, style, cwd.as_ref().ok())
279		};
280
281		let mut f = BacktraceFmt::new(fmt, style, &mut print_path);
282		f.add_context()?;
283		for frame in frames {
284		let mut f = f.frame();
285		if frame.symbols.is_empty() {
286		f.print_raw(frame.frame.ip(), None, None, None)?;
287		} else {
288		for symbol in frame.symbols.iter() {
289		f.print_raw_with_column(
290		frame.frame.ip(),
291		symbol.name.as_ref().map(\|b\| SymbolName::new(b)),
292		symbol.filename.as_ref().map(\|b\| match b {
293		BytesOrWide::Bytes(w) => BytesOrWideString::Bytes(w),
294		BytesOrWide::Wide(w) => BytesOrWideString::Wide(w),
295		}),
296		symbol.lineno,
297		symbol.colno,
298		)?;
299		}
300		}
301		}
302		f.finish()?;
303		Ok(())
304		}
305		}
306
307		struct LazilyResolvedCapture {
308		sync: Once,
309		capture: UnsafeCell<Capture>,
310		}
311
312		impl LazilyResolvedCapture {
313		fn new(capture: Capture) -> Self {
314		LazilyResolvedCapture {
315		sync: Once::new(),
316		capture: UnsafeCell::new(capture),
317		}
318		}
319
320		fn force(&self) -> &Capture {
321		self.sync.call_once(\|\| {
322		// Safety: This exclusive reference can't overlap with any
323		// others. `Once` guarantees callers will block until this
324		// closure returns. `Once` also guarantees only a single caller
325		// will enter this closure.
326		unsafe { &mut *self.capture.get() }.resolve();
327		});
328
329		// Safety: This shared reference can't overlap with the exclusive
330		// reference above.
331		unsafe { &*self.capture.get() }
332		}
333		}
334
335		// Safety: Access to the inner value is synchronized using a thread-safe
336		// `Once`. So long as `Capture` is `Sync`, `LazilyResolvedCapture` is too
337		unsafe impl Sync for LazilyResolvedCapture where Capture: Sync {}
338
339		impl Capture {
340		fn resolve(&mut self) {
341		// If we're already resolved, nothing to do!
342		if self.resolved {
343		return;
344		}
345		self.resolved = true;
346
347		for frame in self.frames.iter_mut() {
348		let symbols = &mut frame.symbols;
349		let frame = &frame.frame;
350		backtrace::resolve_frame(frame, \|symbol\| {
351		symbols.push(BacktraceSymbol {
352		name: symbol.name().map(\|m\| m.as_bytes().to_vec()),
353		filename: symbol.filename_raw().map(\|b\| match b {
354		BytesOrWideString::Bytes(b) => BytesOrWide::Bytes(b.to_owned()),
355		BytesOrWideString::Wide(b) => BytesOrWide::Wide(b.to_owned()),
356		}),
357		lineno: symbol.lineno(),
358		colno: symbol.colno(),
359		});
360		});
361		}
362		}
363		}
364
365		// Prints the filename of the backtrace frame.
366		fn output_filename(
367		fmt: &mut fmt::Formatter,
368		bows: BytesOrWideString,
369		print_fmt: PrintFmt,
370		cwd: Option<&PathBuf>,
371		) -> fmt::Result {
372		let file: Cow<Path> = match bows {
373		#[cfg(unix)]
374		BytesOrWideString::Bytes(bytes) => {
375		use std::os::unix::ffi::OsStrExt;
376		Path::new(std::ffi::OsStr::from_bytes(bytes)).into()
377		}
378		#[cfg(not(unix))]
379		BytesOrWideString::Bytes(bytes) => {
380		Path::new(std::str::from_utf8(bytes).unwrap_or("<unknown>")).into()
381		}
382		#[cfg(windows)]
383		BytesOrWideString::Wide(wide) => {
384		use std::os::windows::ffi::OsStringExt;
385		Cow::Owned(std::ffi::OsString::from_wide(wide).into())
386		}
387		#[cfg(not(windows))]
388		BytesOrWideString::Wide(_wide) => Path::new("<unknown>").into(),
389		};
390		if print_fmt == PrintFmt::Short && file.is_absolute() {
391		if let Some(cwd) = cwd {
392		if let Ok(stripped) = file.strip_prefix(&cwd) {
393		if let Some(s) = stripped.to_str() {
394		return write!(fmt, ".{}{}", path::MAIN_SEPARATOR, s);
395		}
396		}
397		}
398		}
399		Display::fmt(&file.display(), fmt)
400		}
401		}
402
403	0	fn _assert_send_sync() {
404	0	fn _assert<T: Send + Sync>() {}
405	0	_assert::<Backtrace>();
406	0	}

Line	Count	Source (jump to first uncovered line)
1		use crate::Error;
2		use alloc::string::String;
3		use core::fmt::{self, Debug, Write};
4		use core::mem::MaybeUninit;
5		use core::ptr;
6		use core::slice;
7		use core::str;
8
9		#[doc(hidden)]
10		pub trait BothDebug {
11		fn __dispatch_ensure(self, msg: &'static str) -> Error;
12		}
13
14		impl<A, B> BothDebug for (A, B)
15		where
16		A: Debug,
17		B: Debug,
18		{
19	0	fn __dispatch_ensure(self, msg: &'static str) -> Error {
20	0	render(msg, &self.0, &self.1)
21	0	}
22		}
23
24		#[doc(hidden)]
25		pub trait NotBothDebug {
26		fn __dispatch_ensure(self, msg: &'static str) -> Error;
27		}
28
29		impl<A, B> NotBothDebug for &(A, B) {
30	0	fn __dispatch_ensure(self, msg: &'static str) -> Error {
31	0	Error::msg(msg)
32	0	}
33		}
34
35		struct Buf {
36		bytes: [MaybeUninit<u8>; 40],
37		written: usize,
38		}
39